THE WASMAN JOURNAL OF BIOLOGY 35(2). 1977. pp. 169-195 YEAR-ROUND SURVEY OF STAPHYLI IDAE OF A SANDY BEACH I N SOUTHERN CALIFOR l A (COLEOPTERA)
R. E. Orth. Ian Moore. And T . W . Fisher
Abstract .-During a once a month year-round survey of the staphylinid population of a sandy beach at Refugio State Beach, Santa Barbara County. California. 35,3 10 specimens representing 31 species were collected. Twen ty-one of the species were considered indigenous to the beach , the remaining 10 species (II specimens) were considered accidental. Most species were seasonal in distribution. Predominantly winter pecies included Cafius lith oclwrinus. C. luteipennis, C. opacus, C. sulcicollis!. H eterotlwps aspera tus, Omalitllll algamm, Oiglmta pacifica. Thinu.w maritima, two uniden ti fied species of Atht!la and Aleoclwra arena ria . Summer ·pecic were Cafius canescens, C. seminitens, Thinopinus picws, Pontamalota opaca, and A leo chara sulcicollis. Hadrotes ('l'assus, Blediusfenyesi, Bryobiota bicolor. Tar phiota geniculata, anti T. pallidipes were encountered most of the year. Different species showed preference for either a pure andy beach or a rocky- andy beach. Spar ity of staphylinids on two occa ion was corre lated with large larval and ad ult fl y population · sugge ting natural biological control of beach flies by rove beetles most of the year.
Introduction Mo t or the in ect found along the seashore of temperate Pacific North America are restricted to a very narrow habitat. The mo t interesting feature of thi eashore habitat i it linear nature. For mo t of it length it is only a few meter wide and transects almost the entire temperate zone of orth America. It extend from outhern Alaska to at lea t Punta Eugenio. Baja California. a distance of more than 3000 mile, . The unusual nature of this exten ive linear habitat offers exceptional opportunities for the study of insect biology (Moore and Legner. 1974). T he intertidal region of Pacific orrh America falb naturally into three distinct zones which occur repeatedly along the coa 1. These zones are: ( I) rocky headlands with ~ubmerged reefs: (2) andy beaches: and (3) salt flats of bays and es tuaries (Moore, 1956: Moore and L egner, 1976). These zones, in turn. may be conveniently divided into ubzones. defined by the reach of the tide. Eac h of th e zones and subzones supports a distinctive assemblage of insec ts which are se ldom found elsewhere (Moore, 1956). Among the LeJTestrial arthropods which may be found in the intertidal regions are mites. pseudo corpions. centipedes, earwigs. bugs, termites. 170 THE WASMANN JOURNAL OF BI OLOGY
Table I. Total number of each species of Staphylinidae collected at Refugio State Beach: 35,3 10 specim ens were collected in all.
Cajius canescens Maklin 239 Cajius seminirens Horn 315 Cajius lirlzoclwrinus LeConte 4247 Cajius /ureipenni.1· Horn 561 Cajius opacus LeConte 101 Cajius sulcimllis LeConte? 32 Hatfrotes cru.Hu.\' Mannerheim 312 Tlzinopinus picrus LeConte 4 Heterotlzops u.\'{Jertlf/1.1' Smetana 4 8/edius fenyesi Bcrnhauer & Schubert 45 10 Omalium algamm Casey 9 Diglouu pacifica Fenyes 17 Bryobiora bicolor Casey 84 Tlzinu .w maritima Casey 202 Pontamalnta opaca LeConte 86 Tarphiow geniwlaw Miiklin 22,712 Tarphiow pt1lliclipes Casey 38 Arhera sp. # I 275 Arhew sp.#2 14 Aleoclzara arenaria Casey 234 Aleochara sulciocollis Mannerheim 1303 Accidentals Aleochara bimaculata Gravenhorst Aleochara species Anoty/us rugosus Fabricius Anotylus species I Aploderus species 2 Lobrathium species Medon species Neobisnius species Philonthus longicomis Stephens Aleocharinae undetermined springtails, ants, parasitic wasps, flies, weevil s, and other beetles. Diptera and Coleoptera comprise the largest percentage of all intertidal insects in California, both in number of spec ies and individuals. Amo ng Coleoptera. Staphylinidae are the most abundant and the most conspicuous. Except for the describing and naming of spec ies, very few studies have been made regarding this fauna. Jones ( 1968) and Meyerdirk (1969) made preliminary ecological studies of Staphylinidae of the intertidal reefs of California, and Moore ( 1964) made such a stud y of a marine salt marsh. Large offshore kelp beds are a conspicuous feature of the Pacific Coast of North America. Masses of seaweed break loose from these kelp beds and wash ashore. This material (wrack) lying on the shore becomes the ultimate VOLUME 35. NUM BER 2 171
Fig. I. Overall view of collecting area at Refugio State Beach showing wrack on the beach. source of food for many seashore animals, probably including most of the seashore insects of the sandy beach. I f left stranded by a high tide, these masses of seaweed may remain on the beach undistu rbed for a few days to a week or more. L arge colonies of insects develop in this wrack (Moore , 1973). Moore and L egner ( 1974) pointed out that the only staphylinid larvae occurring in wrack in outhern California were occasional larvae of Cafius (Hadrotes larvae al o occur there) and that the developmental period of the e in ect probably takes place elsewhere. T he population buildup of adult in ects usually take place in j ust a few days. T hey peculated that development of the larvae probabl y occurs deep in the sand, and that adult insects are attracted to the wrack as a location where prey could be found. Craig ( 1970), L eech and Moore ( 1971). and James et al. ( 197 1) have dis cussed some aspec ts of the ecology of the insects inhabiting sand y beaches, but much more work remains to be done. T he fauna of this zone in southern California is endangered due to the removal of wrack from the beaches by the park and recreation departments of the state and counties (M oore and Legner, 1972). A consequent need to undertake further studies soon is ap parent. This study was initiated in an effort to determine the qualitative and quan titative composition of the adult staph ylinid fauna of southern California 172 THE WASMANN JOURNAL OF BIOLOGY
Fig. 2. Rocky area at Refugio State Beach showing wrack trapped among the rocks. beach wrack. Monthly visits to Refugio State Beach, Santa Barbara County, California, were made for more than a year for the purpose of determining if the indigenous wrack species were cyclic. The frequency of encounter of these beetles should indicate whether the staphylinids were comprised of seasonal populations or were static throughout the year. A total of 35,310 staphylinid beetles (Table 1) was collected, mounted or preserved in alcohol , and studied in the course of this survey.
Refugio State Beach Refugio State Beach (Figs. 1 and 2) , Santa Barbara County, California. li es at 34°28'N latitude. 120°04'W longitude approximately 250 miles (400 km) north of the Mexican border. The California coastline, in general, runs northwest and southeast. However, much of Santa Barbara County's coast line, including the region of Refugio State Beach, runs east-west. From near its junction with Ventura County to the south for more than 20 miles, the coastline runs due west to Point Conception; then, once again, resumes it s northwes terly direction. Point Conception is considered to be a barrier to the spread of some seashore insects (Moore and Legner, 1976). Refugio State Beach is near the northern limit of the Southern California Marine Province. VOLUM E 35. NUMBER 2 173
24° ...... 1/) ::;, ·v; 22" Q) (.) '-' 20° w cr ~ 1- 18° SEP. OCT. NOV. DEC. JAN. FEa MAR. APR MAY JUN JUL. AUG. Fig. 3. Ocean temperatures at Refugio State Beach during 1976 and 1977. Refugio State Beach is a composite of beach habitats. The main park beach is and. In contras t, the western collecting limit extend as a rocky promontory into the Pacific Ocean. The base of the headland in thi area arches in a southerly direction; near the high tide level is a linear mass of stones which range in size from small beach pebbles to very large boulders. When the tide is out, an essentially sandy beach is exposed below the rocky area. East of the main state beach, a sanely beach continues for nearly one mile where it is terminated by a rocky head land. ln the spring and ummer months, a wide sandy beach is present in front of the main ca mpground. Progressing west from the cam pground area, the beach gradually becomes rocky, but the rocky area is not extensive in su m mer. In the fall and winter months, much sand i removed from the beach by the action of the ocean so that the western rocky area i greatly enlarged . and the sand y beach i reduced in size. A s the easons progres and summer approache . and i:. agai n deposited along the beach until it again assumes its summer condition. Refugio State Beach is well suited for staph ylinids a there i generally an abundance of wrack along the sandy beach. The wrack remains undis turbed except for tidal changes that may either deposit additional material or remove that which has been previousl y deposited. T he rocky area with its boulders, at times, becomes festooned with kelp and other debris that washes ashore. Beneath and within the masses of decaying wrack there is a supply of invertebrates (insec ts, other anthropocl s, molluscs, worms, etc.) in various stage s of development. T hese ma y serve as food for the staph ylinids that occupy the wrack. 174 THEWASMANN JOURNAL OF BIOLOGY The ocean temperatures at Refugio State Beach (Fig. 3) ranged from a low in March and April of 13.3°C (56°F) to a high of 21.7°C (7 1°F) in October. At Refugio State Beach starting in June and continuing throughout the summer months, black crude oil (beach tar) floated ashore and formed lit toral deposits along the seabeach at tidal levels. During the winter months, tar was not present. The tar may be in part the result of oil spills from tankers or offshore wells. According to Evans ( 1970), "Some natural oil seepage occurs off Coal Oil Point approximately 10 miles west of Santa Barbara, and other areas along the California coast and, this could also contribute to oil deposits on the nearby rocks and beaches. ,. In 1969, a major oil spi ll occurred off Santa Barbara. Evans ( 1970) said , " According to Allen ( 1969) irregular stretches of coastline amounting to more than 100 miles were affected by the oil in the two-month period following the oil spill. ·Heavy' deposits (several inches of dark black crude oil over the entire tidal zone) occurred near the Santa Barbara-Ventura area while 'moderate' to 'light' and ' very light' de posits occurred in other areas." To this day, hardened tar, probably from that spill , still remains at very high-tide levels around the rocky point at Refugio State Beach. lt is not known what impact fresh tar deposits have had on the staphylinid population of Refugio State Beach. Materials and Methods The collecting method used was similar to that described by Moore (1954) for collecting staphylinids from manure. Sand and small bits of debris, along with insects from beneath the wrack, were troweled into a plastic bucket approximately two-thirds fulls of seawater. The sand and a portion of the insects sank, but within a few seconds the staphylinid beetles surfaced, having trapped an air-bubble on the dorsal surface of the upturned abdomen. Once the insects surfaced, they did not attempt flight but clung to the float ing debris or the side of the bucket. The surface of the water was then skimmed with a small section of fine-meshed pliable plastic screen. The screen with its debris and clinging insects was immediately immersed and agitated in a quart size widemouthed plastic container about half full of 50% alcohol. As this process was repeated, it occasionally was advantageous to remove excess debris from the surface of the alcohol. Separate containers were used for collecting from different habitats. Once collecting was com plete, the material was stored in a chilled ice chest until further separation could be accomplished in the laboratory. The drawings represent the first comprehensive illustrations of the sandy beach staphylinids of southern California. All illustrations were drawn by R. E. Orth from specimens taken at Refugio State Beach during this survey. VOLUME 35. NUMBER 2 175 Fig. 4. Cajius canescens Maklin. Fig. 5. Cajius seminilem Horn. Fig. 6. Cajius /iJiwdwrinus LeConte. Fig. 7. Cajiu ~ lllleipenni.f Horn. 176 THE WASMANN JOURNAL OF BIOLOGY ::._~:l 1\ . ) • 1 •1 111 111 9 YiI Fig. 8. Cajius opacus LeConte. Fig. 9. Cajius sulcicollis LeConte. ' )' I ~ I.Omm ] 1 Fig. 10. Hadrores crassus Mannerheim. Fig. I I. Thinopinus picrus LeConte. 178 THE WASMANN JOURNAL OF BIOLOGY Fig. 16 . Bryobiota bicolor Casey. Fig. 17 . Thinusa maritima Casey. Fig. 18. Pontamalota opaca LeConte. Fig. 19. Tarphiota genicula/a Miiklin . VOLUME 35, NUMBER 2 179 Fig. 20. Tarpllio1a pallidipes Casey. Fig. 21. Alllew species No. I. Fig. 22 . Alhe/(1 species No. 2. Fig. 23 . Ah,ocllara are11aria Casey. 180 T H E W ASMANN JOURNA L OF BIOLOGY I Hmm 24 Fig. 24 . Aleochara sttlcicollis Mannerheim. R es ul ts Key to the Subfamilies of the Marine Staphylinidae of Southern California I. Antenna! fossae located on the upper surface of the head near a line drawn through the a nterio r margin of the eyes Aleocha rinae - Antennal fossae located at the front or side margin of the head 2 2. Head wi th a pair of ocelli locate d on a line drawn through the pos- terior margin of the eyes Omaliinae (Omalium a/gorum Casey) - Head without ocelli 3 3. Second s ternite present (seven ventral abdomina l segments visible) Oxytelinae (Bledius f enyesi Bernha uer & Schubert) - Second sternite absent (six ventral a bdominal segments visible) 4 4. Side margin of pronotum apparently single Quedii nae (H eterothops asperata Smeta na) - Sid e margin of pronotum double 5 5. T he two late ral cari nae of pronotum distinctly separa te at ante ri or angle Xanthopyginae -The two lateral carinae of pro notum united before anterior angle Staphylininae (Cafius) VOLUME 35. NUMBER 2 181 Key to the Aleocharinae of the Sandy Be ac he ~ of Southern California I. Anterior tar~ us 5-segmented 2 - Anterior tarsus 4-segmented 3 2. Pronotum densely regu larly sculptured Aleoclwra arenaria Casey - Pronotum sparsely irregularly sculptu red Aleoclwm .wlcicollis Mannerheim 3. M iddle tarsus 5-segmented 6 - Middle tarsus 4-segmcnted 4 4. Maxillary palpus about as long as anterior tibia Diglotta pacifica Fenyes - Maxillary palpu s much shorter than anterior tibia 5 5. Ligula bifid Thinu.HI maritima Ca ey - Ligula imple Bryobiota hicolor Casey 6. Pubescence of pronotal disc longitudinal Pontnmalota opaca LeConte - Pube cence of pronotal disc transverse 7 7. Middle coxal cavities margined by a carina; second antenna! egment not longer than third 9 - Middle coxal cavitie unmargined; second egment longer than third 8 8. Leg piceus Tarphiota {feniculaw Maklin - Legs testaceous Tarphiota pallidipes Casey 9. Tenth anten nomere elongate; tactile setae of tenth an tennorncre shorter than segment ; antennae as dark as head A theta No. I - Tenth antennomere tran sverse; tactile setae of ten th anten nomere longer than segment; an ten nae paler than head Atheta No. 2 Key to the Xanthopyginae of the Sandy Beaches of Southern California I. Elytra ovoid. overlapping at suture Thinopinus pictus LeConte - Elytra quadrate. not overlapping at suture Hadrotes cra.!>sus Mannerheim Key to the Species of Cafius of Southern California. Exclusive of C. decipiens LeConte I . Pronotum not longer than wide 2 - Pronotum longer than wide 3 2. Sternites 5 and 6 not more densel y punctured than 4; pubescence golden ca 11 escells Maklin - Sternites 5 and 6 distinctl y more de nsely punctured than 4; pubes- cence silver y semi11ite11s Horn 182 THE WASMANN JOURNAL OF BIOLOGY 1000 300 ,., 100 I \ I ' I \ 30 I \ \ \ 10 ·--·\ 'a)' \ 0 u 3 (/) 0> I 0 0 .l. MAY JUL. JUN. AUG. ~ 1000 Cof ius lithoc harinus -- ~ 300 Cafius futeipennis 0 w 100 • t, I- I' I \ u '' I ' I \ w , / '' 1/ ' • , I \ 30 \ .I ·--· ' •' I =l I I 0 I \ (.) 10 I: ' '• (/') z 3 I ', w : '~ ~ I I (.) I w 0 0.. MAY JUL. SEP. NOV. FEB. APR. JUN. AUG. (/') 1000 Cofius opacus --. I.J... 0 300 Coflus sulcicollis ?•-- · cr w (]) 100 ~ :::> z 30 10 3 I 0 MAY Fig. 25. Monthly collections of the staphylini<.l beetles of Refugio State Beach. 3. A ntenna! segments longer than wide opocm L eConte Tenth antenna! segmen t not longer than wide 4 4. Elytra at leas t in part paler than pronotum 5 - Elytra not paler than pronotum Slllcicollis L eConte? VOLUME 35. UMBER 2 177 I•••• I) Fig. 12 . H t•u•rothops fnp<'ratus Smetana. Fig. 13. Bletlim fenyesi Bernhauer & Schubert. Fig. 14 . Omalium a /~artl/11 Casey. Fig. 15 . Di}llotltl pacifica fcnycs. VOLUME 35. NUMBER 2 183 crassus - 30 10 'Q)' 8 3 (/) 0> .2 I 300 0 w 1-u w _J _J 8 10 (f) z w ~ I u w o~-.~~~.-~~~~~~,-~~~-r-r~ Cl. MAY FE B. APR. JUN. AUG. (f) LL Omalium algarum - 0 300 Diolotta pacifica a::: Bryobiota bicolor ~ 100 ~ . ~ .··: z 30 .•· 10 .~· .. : ··.•.... • I . 0~~--~~~~~~~~~~~--~~~~~ MAY JUL. SEP. AUG. 1976 Fig. 26. Monthly colleclions of lhc staphylinid bee lies of Refugio Slale Beach. 5. Elytra tes taceous throughout; head more finely and densely punc- tured beneath than above /ut eipennis Horn - Elytra usually pale only along the posterior margin: head as coarsely and sparsely punctured beneath as above litlwdwrinus LeConte 184 THE WASMANN JOURNAL OF BIOLOGY 1000 Th inusa mar it ima - Pontomalota opaca ·--· 100 30 10 I \ ~ I \ 0 I \ ....• \ u 3 / '.;... ' VI ' I 0'> I --- -·--· 0 o~--~r-~4-~~~~rrr-~,--r~~~~~~ FEB. APR. JUN. ~ 10.000 1,/) Tarphioto Qeniculoto - -;;;3000 w t> 1ooo w j 300 8 100 (/) z 30 w ~ u 10 w 0 a.. MAY FEB. APR. JUN. AUG. (/) 1000 lL. Tarphiota pall i di~es 0 300 0:: w (l) 100 ~ :::> z 30 10 3 I 0 Fig. 27 . Monlhly collections of the slaphylinid beetles of Rt:fugio Stale Beach. Cajius. Members of this genus are moderate sized (6-15 mm) insects which are found on the seashore or the margins of rivers near the sea throughout the world. Fifty-two species have been described of which eight have been reported from the Pacific Coas t of North America. Seven of these ------VOLUME 35. NUMBER 2 185 ...... Q) Atheto sp. I - 0 0 A theta sp. 2 •--• IJ) 01 0 I 30 E Q) IJ) 10 '-' Cl w 3 f- u w I _J 0 _J MAY JUL. SEP. FEB. APR. JUN . AUG. 8 1000 Aleochoro orenorio -- (/) z 300 Aleochoro sulcicollis •--• w ::.:E 100 .-· u .-- \ \ w : \ a. 30 I (/) I I lJ.... 10 I I 0 I o:; 3 ' w ! CD ::.:E I ::::> 0 z MAY Fig. 28. Monthl y collections of the staphylinid beetles of Refugio State Beach . are listed from California, six of which were taken (Table I) on this survey. James et al. ( 197 1) reported that these insects lay their eggs deep in the sand where the larvae prey on crustaceans and other invertebrates. The larvae are rarely found in wrack. whereas the adult may be abundant in that habitat. Cafius canescens Maklin (Fig. 4). ln contrast to most species of the genus. the body of this specie!> as well as that of C. seminirens i robu t, with the pronotum not longer than wide. The sculpture of the pronotum of both species is al o more coarse and irregular than that of the other species. Cafius canescens differs from C. seminirens not only by the charac ters given in the key, but in having longer antennae, and by having the acrocostal suture of first two tcrgites gen tl y curved . not with a posteriorly directed central cusp as in C. se111inirens. The head is densely alutaceus throughout. T his is a common species along the entire Pacific coastline. In southern California, it is abundant in summer. Individuals can be seen flying and alighting on the 186 THE WASMANN JOURNAL OF BIOLOGY sand on mo t beaches . They ar e usually found in wrack in numbers. When the wrack is disturbed. they quickly run or fly away. T he larva and pupa were de cribed by James et al. (197 1) . A t Refugio State Beach. this species was found all months of the year except January. It was most common in the spring. The sandy beach was favored over the rocky area. Cafius seminitens H orn (Fig. 5). This species is quite similar to C. ca nescens, but differs not only as given in the key, but in ( I) the shorter antennae, (2) th e acrocos tal suture of tergites one and two having a central posteriorly directeu cusp, and (3) the disc of the head usually being shiny. The average size is slightly larger than that of C. canescens. Its range is the same as that of C. canescens. but it is generally less common. The habits of the two species are similar. The larva (James et al.. 197 1) is quite distinc tive in that the urogomphus is one-segmented and spherical whereas that known for other species of Cafius is two-segmented and cylindrical. This specie was taken at Refugio State Beach throughou t the year. but most commonl y in April. It was largel y restricted to the sandy area of the beach. Cafius fithoclwrinus L eConte (Fig. 6). T his pecies i distinct from all other local species of Cafius except C. luteipennis in that the el ytra are partly or entirely paler than the rest of the insect. l n C. lu teipennis, the elytra are always entirely pale yellow which is rarely the case with C. liTh ocharinus. l n C. litlwcharinus, the elytra arc usually dark with narrow pale apices. The pale color is variable in extent, in some spec imens occupying mos t or, rarely, all of the elytron. The two species are easil y separated by the puncturation of the under sUlface of the hea d as noted in the key. T his specie i known from Washington to Baja California. lt is known to fly in swarms along the beach in winter , probably on dispersal flights (L eech and M oore, 197 1). A t such times it can be found under almost every bit of debris on the beach. The flights look deceptively like swarms of flie . The larva and pupa were de cribed by James et al. ( 197 1). A t Refugio State Beach. this species was absent during July and August and was most abundant in midwinter. It was most often taken from the rocky area of the beach. Cajius luteipennis H orn (Fig. 7). Thi species is easily recognized by its traw colored elytra. It averages a little smaller than C. litlwclwrinus and is noticeably lender. It can always be separated from C. litltoclwrinus by the characters given in the key. I t is known from Washington to Baja Cal iforn ia. It i a winter species. never very common. T he larva and pupa were described by James et at. ( 197 1) . The occurrence or C. luteipennis <.luring the survey was largely from Oc tober through April. It was primarily confined to the rocky section of the beach. VOLUME 35, NUMBER 2 187 Cajius opacus LeConte (Fig. 8). This species is exceptional among our s pecies of Cajius in that all of the antenna! segments are distinctly longer than wide. It is a slender spec ies whose integume nt is finely and densely sculptured throughout. The color is usuall y pa le brown, but dark specimens occur. This species has usually been rare and. until this survey, was known from no farther no rth than San Diego (Moore and Orth. 1977). It probably is o ne of those species of insects whose range is restricted to south of Point Conception. The developmental s tages are unknown. At Refugio State Beach it was found o nl y on the rocky part of the beach and during a few winter and spring months. Cajius sulcicollis LeConte? (Fig. 9) . T his species resembles C. opacus in its slender build and uniform color. H owever, the outer antenna! segments are not lo nger than wide. The species is rare in most collections. It has not previously been reported fro m north of Sa n Diego (Leach a nd Moore, 1971). It was found at Refugi o State Beach mostly from November through April a t the rocky section of the beach. The original and s ubsequent descriptio ns of C. sulcicollis LeConte a nd C. decipiens LeConte are not suffic ientl y clear to indicate dis tinctions between the two; nor have two separate s pecies been encountered which fit these two descriptions. The problem can be resolved only by a revision of the genus. A revisio n of the North American species of Cajius is planned for the near future. fladrotes crassus Mannerheim (Fig. 10). This is a la rge (up to 20 mm) reddish-brown to dark piceous parallel species known from southern Alaska to Baja California (Moore and Legner, 1975). One other species of this genus has been described from New Zealand, a nd a single species of a similar genus, Hadropinus , from a Japanese seabeach. Hadrotes crassus is wingless and slow-moving. It is usua ll y encountered in well decayed seaweed, but seldom seems to be abundant. The larva (Moore, 1964), dark and sluggish, is found only occasionall y in seaweed. During this survey adults occurred throughout the year, with the greatest abundance in the spring and fall. rt commo nl y occurred in small cell-li ke pockets in the sand beneath la rge stones as well as under wrack. Its fre quency of occurrence at Refugio State Beach may have been due to large masses of seaweed being trapped for considerable periods of time by large boulde rs on the beach. Thinopinus pictus LeConte (Fig. II) . This large (up to 20 mm) beach insect has been called the Pictured Rove Beetle. It is robust with a somewhat inflated abdomen and with ovoid overl apping elytra . The general back ground col or usuall y matches the sand in which it is found . It has distinctive, but variable dark ma rkings on the head, e lytra, pronotum. and abdomen. It is fou nd from British Columbia in to Baja California. It is polytopic in the no rthern part of its range where dark po pulations occur on certain beaches 188 THE WASMANN JOURNAL OF BIOLOGY (Malkin 1958; Moore, 1977). This is the only species in the genus. It is wingless and relatively slow-moving. It li ves buried in the sand and is sel dom found in wrack. It is nocturna l on the wet sand following a receding tide where it preys on amphipods (Craig, 1970). The larva was i.llustrated by Boving and Craighead ( 193 1). The single specimen which was found on each of three occasions (May, June. and July) during this survey is considered fortuitus in wrack. Heterothops asperatus Smetana (Fig. 12). This species belongs to a mod erately large genus found in wet biotopes usually distant from the seashore. One other seashore s pecies is known from England. In the subfamil y to which it belongs (Quediinae), the s ides of the prothorax are strongly de fl exed so that it appears to have a single border rather than a double one. T his genus is distinct in its subfamily in that the last segment of the maxillary palpus is distinctly narrower than the penultimate segment. This character is shared with members of the Aleocharinae which can easily be distin guished by the characters given in the key. This is a moderate sized (to 5.7 mm) shin y dark insect with the abdomen tapered to the apex. It ranges from British Columbia to southern California. Our four specimens were taken in the transition zone between the rocky and the sandy areas of the beach in January. Bledius fenyesi Bernhauer and Schubert (Fig . 13) . This is a large genus whose members are usually found along the sandy or muddy margins of fresh water streams or ponds. However, many species are known from salt marshes and a few inhabit sandy beaches. Bledius fenyesi is a moderately s maU species (4 mm) with the first antenna! segment much elongate and with fossorial anterior tibiae. It has a number of discrete color forms ranging from pale yellow to dark brown with different parts of the body displaying those colors in different combinations. This species is usuall y confined to the seabeach south of Point Conception being replaced to the north by a very si milar species, B. monstratus Casey. This species is usually found in well decayed seaweed. The larva is unknown. At Refugio State Beach, it was found year-round except October and was extremely abundant from February through September. Omalir11n algarum Casey (Fig. 14). This species is generall y rare in south ern California. It is about 5 mm long, somewhat robust and with longer elytra than is usual for staphylinids. It is easil y recognized among the other beach beetles by the pair of ocelli on the posterior elise of the head. The colo r is a shade of brown very close to that of wrack. The integument of this species is strongly alutaceus, a character not common in the genus. It is reported from British Columbia to southern Cali fornia. The develop mental stages are unknown. At Refu gio State Beach, one specimen was taken in February and four in both March and November. VOLUME 35 , NUMBER 2 189 Diglotta pacifica Fenyes (Fig. 15). Because of their unusual mouthparts, members of this genus are placed by themselves in a small tribe. Diglottini. All of the few species are marine. They are known from Europe, the Red Sea, and Singapore. Diglotta pacifica is quite small ( 1.5-2.0 mm), dark, with the base of the pronotum and the bases of the elytra constricted pro ducing an unusual appearance. The tendency to curl into a tight sigmoid curve at death is also distinctive. Moore ( 1975) mentioned finding this spe cies on a beach at night in company with the more abundant Thinupinus picrus and Thinusa maritima. It is rare in wrack but in winter can be taken in numbers on some beaches by sampling with a plunger in the sand (Dale Straughan, pers. comm.). The early stages are unknown. Fifteen specimens were taken in January and two in February at Refugio State Beach. Bryobiota bicolor Casey (Fig. 16). This is a rare in sect. Although Casey ( 1885) stated," ... San Diego (California). This species is extremely abun dant under the densely packed seaweed thrown up on the shores of the inner harbor in the Spring of the year.'', this was probably an unusual situation causing temporary abundance. It is a small (2.0-3.0 mm) linear insect largely ferrugineous with the abdomen partly dark. Along with Thin usa maritima, the anterior and middle tarsi are four-segmented, and the posterior tarsi are five-segmented. Unlike T. maritima, the vertex of the head is longitudinally impressed at the base. Thinusa maritima is a little smaller with larger eyes. Bryobiota bicolor is the only species in the genus. It ranges from B1itish Columbia to southern California. Nothing is known of the developmental stages. At Refugio State Beach it was found throughout 1977 only and was never common. It occurred on the rocky section of the beach. Thinusa mari1ima Casey (Fig. 17). This species is placed in the tribe Bolitocharini of the subfamily Aleocharinae along with Bryobiota biculor because of its tarsal formula (see the key). It is a little smaller than B . bicolor, slender, largely dark with the tip of the abdomen reddish. The eyes are large, occupying more than half of the side of the head, and the elytra have the outer margin noticeably longer than the suture. Although several species have been described, all from Pacific North America, only two names are now considered valid. Thinusa jfetcheri Casey occurs from Alas ka to British Columbia and T. maritima from Washington into Baja Cali fornia. Thinusa maritima is not common in wrack. but can sometimes be found in numbers on the wet sand at night (Moore, 1975). The early stages are unknown. At Refugio State Beach it was found in wrack in the late spring and summer but was absent in the fall. Pontamalota opaca LeConte (Fig. 18). This is a small (4 mm) pale species with the head and the base of the abdomen infuscate. Five species of this 190 THE WASMANN JOURNAL OF BIOLOGY genus are at present listed , a ll from the Pacifi c Coast of North America. Probably only three of these represent valid species. The genus has the same tarsal formula as Tarphiota and Atheta, fo ur segments on the a nterior tarsus and fi ve segments on the others. Pontamalota opaca can be recog nized by its pale color a nd the fact that the pubescence of the pronotum does not stream out laterall y from the midline , but tends to be longitudinal. Pontamalota opac:a is known only from south of Point Conception. It is replaced north of Point Conception by P. c:alifornica Casey and still farther north by P. lu c:tuosa Casey, both dark species. Pontamalota opaca, like Thinusa maritima , is nocturnal on the wet sand and is only rarely present in wrack (Moore, 1975) . Nothing is known of its developme nt. At Refugio State Beach it was most common in the spring and summer and not present in September and October. Tarphiota . Members of this genus a re known only from the Pacific Coast seabeaches of North America. They resemble members of the genus A theta , but can be distinguished by the characters given in the key. The lateral streaming of the pubescence on the pronotal elise is more noticeable in members of this genus than in those of Atheta. Tarphiota geniculata Maklin (Fig. 19). This is the most common staph ylinid in wrack. 1t is found from Alaska in to Baja California. It is quite small (2 mm) and uniformly dark. In spite of its great abundance, the larvae are unknown. At Refugio State Beach it was extremely abundant in April, July, August , and September; entirely absent in October; and present the other months. Tarphiota pallidipes Casey (Fig. 20). This species is larger than T. genic ulata (3-4 mm) . It closely resembles T. genicu.lata , but has pale legs. It is found throughout California and into Baja Califo rnia. It may have a more northern distribution, but has not been so recorded. Tarphiota fuscicola Makli n is found from British Columbia to Alas ka. lt is about the same size as T. pallidipes, but has dark legs. As with T. geniculata, the early stages a re unknown. At Refugio State Beach, T. pallidipes was collected sporadicall y, but it was never common. A theta . This is a very large polymorphic genus of worldwide distribution. T he species are mos tl y small , somber colored , and usually require careful attention for their d iscrimination. T he necessary work to distinguis h the species has been done for parts of Europe; for the rest of the world, onl y sho rt inadequate descri ptions or no descriptions at aJl are available. Con sequentl y, we consid er it imprudent to state even provisional determinations of these species. Atheta species No. I (Fig. 2 1) . T his species and the next are very s imilar in appearance. However, we are confident that two species are distinct because, with ample series of specimens of each, no intergrades occur. VOLUME 35. NUMBER 2 191 Several males wifh extruded genitalia are re presented in each serie . The most reliable characlers appear to be in the antennae. In this species, all the antenna! segment are a long or longer than wide. The setae on the outer antenna! segments are of nearly uniform length and shorter than the length of the egments on which they originate. At Refugio State Beach this species was alway more abundant than Ath er a species No. 2. It wa present during the winter and spring months. Atheta species No. 2 (Fig. 22). This species is similar to A theta species No. I but can be distinguished from it by the pen ultimate antenna! segments which are transverse. Each outer an tenna! segment bears, bes ides the short se tae as are found on A th eta species No. I , a few prominent setae which are longer than the segment on which they originate. Atheta species o. 2 was not as abundan t as Atheta species No. I . It occurred from December through April except for its absence in March. Aleochara. This is a large genus of worldwide occurrence. Several species are found aJong the eashore of Europe and America. L arvae of members of this genus are ectoparasites on the pupae of flies within the pupa ria. They are particularly common around decaying organic matter which attracts ftie . Be ides the character given in the key, the tructure of the pal pi is unu ual. T he maxillary palpus is five-segmented with rhe fourth egment narrower than the third and with the fi fth egment a minute appendage of the fourth. Aleoclwra arenaria Casey (Fig. 23). This species is of variable ize (3- 7 mm) probably depending on the size of the fl y pupa which it parasitized. It is generally dark with the elytra often pale. T he integument is very densely and regularly alutaceous throughout. Aleocharia arenaria is round from British Columbia to Baja California. I t is usually rare in southern California but is sometimes abundant where large masses or seaweed occur. H osts are not recorded for it. At Refugio State Beach it was absent for mo. t of the first year but fairly common in the winter months at the rocky ection of the beach. During the second year. it appeared in numbers during Augu t. Aleochara sulcicollis Mannerheim (Fig. 24) . T his usually is one of the most common staphylinids of the sandy beaches. It is variable in length (2.5-5 mm). In appearance it is so strikingly different from A. are11aria that they might be thought to belong to different genera. Individuals are always quite dark throughout with the integument polished and shiny and with irregular coar e puncturat ion. The anterior tibiae are strongl y fossorial. T his spec ie i found from A laska into Baj a California and has been reported from Chile. Host record s are lac king. At Refugio State Beach it was found in all months of the year except October but was most common in summer. A ccidental species . The following were considered accidental individuals 192 T HE WASMA NN JOURNAL OF BI OLOGY whi ch were attracted to the decaying orga ni c matter while fl ying in the vicinity: Aleochara bimaculara Gravenhorst. Aleochara sp., Anoryl11s m goslls Fabri cius, Anorylus sp. , Aplodem s sp., Lobrarhi11m sp., Medon sp .. Neobisnius sp. , Pllilontlws longicornis Stephe ns and a specimen of unde termined genus in the subfamil y Aleochari nae. T he general habits of A leo chanl are discussed under A . arenaria; A. himaculata is very common in fi eld manure. Anotylus is a commo n northern inland genu s whose presence here is unexplained (Moore and Orth, 1977). Some species of Aplodem s occur in fi eld manure. Philonrlws longicomis Stephens is cosmopolitan and common in accumulated manure of da iri es, poultry ranches, etc . Members of Lobrarhitllll, Medon, and Neobisnius are ofte n found under debris a lo ng the margins of streams and ponds. Discussion a nd Conclusio ns Of the 19 species of Staphylinidae previously reported to be indigenous to the sandy beaches of California, all but one (Cafius decipiem LeConte?) were coll ected at Refugio Sta te Beach during this survey. T hree additional species (Heterorhrops asperara , Arhera species No. I and A rhera species No. 2) are reported for the fi rs t time in southern Cali fornia. A few ind ivid uals of 10 species considered to be accidental were also encountered o n the beach. O ne conclusion to be drawn from the present study is tha t the abunda nce of the various s pecies of Staphylinidae restri cted to wrack in southern Cal ifornia is markedly seasonal. So me species are present or most abundant o nl y at one time of the year. while o the r s pecies are found at another time. Of those species which were ta ken in large enough members to definitely indicate seasonal distributio n, onl y H adrotes crassus showed an appare ntl y uniform distributio n throughout the year. Cafius lirhocharinus, C. lureipennis, and Aleochara arenaria were pre viously considered rare , but we found them to be common in the win ter and rare or absent only in the summe r. Cafius opacus, C. sulcicollis"!, Omalium a/gam m, Dig/of/a pacifica. and bo th species of Arhera were absent in sum mer but present (although generally scarce) in the winter. The fo llowing species were abundant or fairly common during the sum mer. but usuall y no t numerous at other times of the year: Cafius canesc:ens, C. seminitens, and Aleochara sulcicollis. T wo species, Bledius fenyesi and Tarphiota geniculata. were fo und throughout the year. They had a large summer populatio n as well as a nother populati on peak in the spring. Tar phiora geniculata was the most common species, comprising more than half of all specimens coll ected. The fo ll owing species are known or th ought to be restricted to south of Point Conception (Moore and Legner, 1975): Cajius opacus, C. sulcicollis"!, VOLUME 35. NUMBER 2 193 Bledius j'enyesi. Dig/of/a pacifiw. and P ontamalota upaca. The other spe cies are found both north and south of Point Conception. o correlation has been found between these two group and the · ea~o n a l di tribution of species. A definite relationship exists between the ~easona l distribution of some species and the type of beach on which they were found . Hadrote.\· crassus. Bleclius j'enyesi. Tarphiota ge11icu/aw, and Aleoclwm sulcicol/i.\· were found throughout the year on both the sandy and rocky types of beache . The last three specie were mos t abundant in the summer on the sand y beach. The following species were found almost exclusively in the winter and were largely res tricted to the rocky section of the beach: Cajius lithoc/l(lriiiiiS, C. luteipen11is. C. opoc:us, C. sulcicollis?. both ·pecics of A theta. and Aleo chara are11aria. On the other hand Cafius canescens, C. seminite11s, Thinusa maritima, and Pontama/ow opaca appeared to be largely restricted to the sandy beach. Cafius canesce11s and C. semi11ite 11 s were fou nd almost entirely in the spring and summer months. In both ections of the collecting area, much sand wa removed from the beach by the action of the ocean in the f all and winter months, leaving the beach much more rocky during that period. However. even in the winter there was an extensive area of sandy beach remaining. Conversely, in the spring and ummer month , additional sand wa!> deposited on the beach. Thu . the exposed rocky area was reduced, but not obliterated. and the staphylinid populations within the limits of the remaining rocky habitat were greatly red uced. The removal of sand in the fa ll and winter and its rede position in th e spring and summer does not appear to be sufficient cau se for the seasona l variation of staphylinicl populations in these two types of beach es. Other factors appear to be involved, but what these fac tor are, we can not conjecture at present. ln the proces of collecting and sorting specimens. it ha!> been noticed that as a population of each species reaches and passes a peak there is an increasing number of individuals with broken appendages. This fact was not explored quantitatively. It has occurred to u that this characteri!> tic of beetle populations. if properly documen ted . could be used as a tool toes timate population age. A men tioned in the introduction. there is no overlap between tho e ma rine specie found on the intertidal reefs. the marine mud flats. and the sand y beaches. This has been well documented in thi survey. Of the 35.310 specimens collected. not a single individual of the spec ie ~ characteristic of the reefs or the mud flat wa encountered, even though a prominent reef and mud Rat are nearby. Prey o f' most staphylinids consists largel y of in ~ec t s. probably in many cases flies and their larvae ( Voris, 1934; Mank, 1923). As !lies an d their larvae are ometimes abundant in wrack, it seem safe to conjec ture that rove 194 T HE WASMAN JOURNAL OF BIOLOGY beetle have an impact on the density of beach flie . Some of our collecting data seems to substantiate this view. During mos t of the months of the survey, staphylinids were coUected in rather uniform large numbers. and flies and their larvae were not abundant. Our field note and charts showing abundance of each species indicate that staphylinids were poorly repre sen ted on the beach in August 1976. Field notes for that month read as follows: " There were extreme numbers of dipterous larvae and pupae in the wrack in the same area usually occupied by staphylinids. ·· A similar. but not quite so pronounced condition, occurred in May 1977. This seems to indicate that the absence of staphylinicls in large numbers allowed rapid mu ltiplication of flies. A pparently a normal staphylinid population would have des troyed most of the fly larvae. We speculate that under normal conditions, beach flies are under relatively good natural control by wrack inhabiting staphylinid ; and that w hen staphylinids are greatly reduced in numbers. beach flies become abundant. It is even possible that eventuaUy some method could be found to utilize these insects for the biological control of noxious fl ie on the beach. Acknowledgments Thank i extended to Christine M . Elder. Connie D. Orth. Eugene K. Orth, Martha H. Orth, Christine Sander , A lex Smetana and Mary Ann Walsh for assi tance rendered. Literature Cited Allen. A. A. 1969. Sant a Barbara Oil Spill. Statement prepared for U.S. Senate Interior Commiuee. subcommitlee on minerals. materials. and fu els. 20 May. 1969. Boving, A. G .. and F. C. Craighead. 1931. 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