The larvae of North European Clairville (Coleoptera, )

ANDERS N. NILSSON & JAN G. M. CUPPEN

Nilsson, A. N. & Cuppcn, J. G. M.: The larvae of North European Colymbetes Claiville (Coleoptera, Dytisciitic). [De nordeuropeiska Colymbetes-afiernas larver (Coleoptera, Dytiscidae).]- Ent. Tidskr. 109: 87-96. Umefl, 1988. ISSN 0013-886x.

ln North , the dytiscid genus Cblymbeies Clairville includes the four species: C dola- brarus (Paykuli), C. /usais (Linnaeus), C. pavkulli Erichson, and C. sl/iarus (Linnaeus.)- Ear- lier tre;tm;nts ;f larvae of this genus are confusing as the larvae described as C. paykulli were misidentifietl. Based on material mainlv from northern Swcden and the we pre- sent an illustratcd identification key to all four species and all larval rnstaIS. Phenological dala from different latitudes are presenied and the liie cycles of the studied species are discussed.

.zl. N. Ni/sson. Depa ment of Ecology, lJniversity of Umed' S'tNl 87 Umed, Sweden' l. G. M. Cuppei, Department of Water Folltuion Control, Laboratory ?f y!qro?iol?8J', Wageningen Agricukuial lJniversiiy, P.O.B.8129,6700 EV Wogeningen, The Netherlsnds'

Introduction North European Colymbetes Clairville includes was based on the examination of larval exuviae, it the four species: C. dolabratus (Paykull), C. /us- probably represents C. striatus. Further, Fal- crrs (Linnaeus), C. paykulli Erichson, and C. kenstrdm who had collected this material had srrlatus (Linnaeus). Galewski (1964, 1968) de- identificd it as C. slridlus. scribed all larval instars of all four species and pro- The main purposc of this paper is to cnable the vidcd keys to their identification. Galewski's identification of larvae of all instars of the North ( 1968) key to third-instar larvae was also repro- European specics of Colymbetes. Somc observa- duced by Nilsson (1982). Howevcr, the larvae of tions on phenology and life history arc presentcd this genus arc very difficult to idcntify to spccies as also. and highly var- larvae of all species arc very similar Methods and material iable in most characters. After the study of many larvae. mainly from northern Swedcn and the Dissected larvae were mounted in Euparal on Netherlands- we have come to the conclusion that glass slides or studied in alcohol with a Wild Ml1 Galewski's ( 1964) description ol C. paykulli is transmission microscope or a Wild M5 stereo- based on larvae that belong to C. striatus. Con- microscope, both provided with a drawing tube sequently, the true larva of C. paykulli is unde- and a micrometer eyepiece. Measurements and scribed, a fact that explains much of the difficulty abbreviations are uscd as in Nilsson (1987). The pxperienccd whcn identifying larvae to species as nomenclature oI lcg sensilla follows Nilsson the keys given by Galewski (1964, 1968) and (1e87). Nilsson ( l9lt2) are useless for the separation of lar- Larvae of C. dolabratus, C. paykulli and C. vae of C. striatus and, C. paykulli. As the distribu- striqtus were collected from several localities in tion of these two common species show a large northern Sweden. Additional larvae of C. dola overlap, problems are severe. Further, the key bratus wcre from Greenland and northernmost characters used by Galewski (1968) are mainly . Besides a single third-instar larva from gradual and often difficult to use unambiguously. the Baltic Island of Gotland and one or two larvac Galewski (1967) also described the pupa of C. of each instar from England, all C. /uscas larvae paykulli. However, as the identity of his material were from the Netherlands. ll8 Anders N. Nilsson & Jan G. M. Cuppen

Figs 1-4. Colymbetes. first-instar larva. head. dorsal aspect. - I . C. paykulli Er.. with marginal clypeolabral setae r.lagnified, - 2. C. fuscus (L.). - 3. C. striqtus (L.), with marginal clypeolabral setae magnified. --4. C. dolabratus (Payk. ).

The idcntity of tlrc larva of C. paykulli is based General remarks on several cases of co-occurrcnce of Iarvae and adults in a region where C. striatus is the only For a general desciption of ColymDs,es larvae we other specics of the genus. As the description of refer to Galewski (1964). The similarity wirh the the larva of C. strians given by Galewski (1964) larvac of Rhantus (s.str.) Dejean is srriking. The was based partly on larvae reared from eggs laid in separating characters given earlier (Nilsson 1987) captivity, their identity must be regarded as cer- are useful, but the number of PD femoral setae in tain. Thc identity of the larvac of the other three the two later instars should be used with some cau- species is based on Galewski's (1964, 1968) de- tion as variation in Colymbetes is considerable. scriptions in combination with co-occurrence of The primary lcg setation of Colymbetes larvae larvae and adults, partly with species in allopatry. shows a few constant differences from that of The studied material is deposited in the collec- Rhantus. Besides the lack of additional tarsal tions of the authors. setae and the spiniform shape of the upper PDi Lamoe of North European Colymbetes 89 seta on all femora in Colymbetes mentioned ear- 5. Abdominal segments l-6 with non-functional, spiracles (Secord instar) 6 lier (Nilsson 19t17), also the tibiae lack the addi- closed, obsolete ...... - Abdominal segments l-6 with functional, dis- tional setae present in AV and PV seriesin Rhan- tinct spiracles present laterally on each tergum /u.r. The secondary setal series on the legs are the (Third instar) ...... I same in both genera, and as variation in setal num- 6. Anterior clypeolabral margin inside lateral an- long as antennomerc 2 bers is considerable, these characters have a low gles more than 2x as (Fig. 13). Head witlth at stemmata 2.4-2.6 mm. diagrrostic value. Urogomphus short, U/LAS l ll-5 (Fig.20). In the first-instar larvae, the bifurcate shape of Met;tibia with l-2 secondary P spines (Fig. 22) the marginal clypeolabral setae in C. paykulli is characteristic, and evidently apotypic. Otherwise - ;i;il ;ii;;;i";;;i ;#;;;;iJ i,i,",^(ill*" gles less than 2x as long as antcnnomere 2 (Figs most diagnostic characters within the genus are 14-15). Head width at stemmata 2.2 mm or less. gradual. The general similarity in larval morphol- Urogomphus long, U/LAS 1.6 or more (Fig. ogy among the Colymbetes species makes a sepa- 2l). Mctatibia in m()st sPecimens without sec- (Fig.23) 7 rate description of the C. paykulli larva unneces- ondary P spines ...... 7. Anlerior clypeolabral margin in ventral view sary. The charactcrs that scparate it from the about as broad as width of first segment of labial other species are illustrated and given in the key. palpus (!'ig. 16). Palpi thicker. apical segment of Further, some important measurements are listed maxillary palpus less than 5x as long as broad (Fig. Protarsus with 3--4 secondary AV in Tab. 1. l8). spines ...,...... ,.... fuscus - Anterior clypeolabral margin in ventral vicw distinctly narrowcr than width of first segment Key to larvae of North European Colymbetes of labial palpus (Fig. l7). Palpi slender, apical l. segment of maxillary palpus about 6x as long as broad (Fig. 19). Protarsus with 5 or more secondary AV spines ...... 8 8. Urogomphus longcr. U/LAS 2.0-2.2. Outer margin of urogomphus with 4-10 spiniform, ycl- low setae dispersed along entire length togethcr with numerous black setae- Legs slender, width of metatarsus at level of primary spine no. 2 sub- equal to or narrower than length of spine (Fig. 24) ...... dolabratus - Urogomphus shorter, U/LAS 1.GI.8. Outer margin of urogomphus with 0-3 spiniform -setae in basal half togcther wilh numerous black selae. Legs less slencler, width of mctatarsus at length of .... PuYkulli Ievel of primary spine no. 2 exceeding - StraiEht or curvcd anterior cllpeolabral margin spine (Fig. 25) ...... eriatus insidc lateral anglcs wilh l!20longand apically 9. lnner margin of mandible with weak median rounded Iamelliform setae (Figs 2-4). Urogom- tooth (Fig. 26). Anterior clypeolabral margin in phus long, UILAS 2.21.7 (Fig. 6). Protarsal ventral vicw thickcr than width of first segment seta no. 7 in most sp€cimens much shorter than of labial palpus (Fis. I 6) ...... ,,...... /ascus tarsalclaws (Fig. 8). Head width 1.4 mm or less - Inner mCrgin of mandible without median ttxrth 3 (Figs 37-28). Antcri(,r clyPeolahral margin in ventral view narr()wer lhan wi(llh ()f first se8- ment of labial palpus (Fig. 17) l0 t0. Anterior clypeolabral margin long. inside lateral angles 2.4-2.5x as long as antennomere 2 (Fig. 27)- Head wilh at stemmata 3.+3.7 mm,Iateral outline subparallel (Fig. 27). Metatibia in most specimens with l-3 secondary P spines (Fig. 22). Urogomphus with 45-50 setae along outer .- margin 1Fig. 29) ...... , ...... paykuLli - Antirior clypeolabral margin short, insidc lat- eral angles 1.9-2.2x as long as antennomere 2 (Fig. 28). Head width at stemmata 3.3 mm or less: latcral outline often convcrging anteriorly (Fig. 28). MetatibiawithoutsecondaryPspines. Urogomphus with 35 or less setae along outcr margin (Figs 30-31) . . .. ll ll. Larva larger, head width at stemmata 3.2-3.3 90 Anders N. Nilsson & Jan G. M. Cuppen

0 02 rhlrr

I r. ------i <___-_____< - O O5mm --..=_:* I \ -,______1"--o o5mm z\\ Figs 5-12. Colynbetes, first-instar larva. - -5-6. Last al ominal scgment with urogomphi. - 5. C. puvkulli Er. - 6..C. triurus (L.). - 7-8- Protarsus. posterior aspect-.- 7. C..paykulli.--8. C. srriatus.--9-i0. Maxilla, ientral aspect. a2.!. fuscus (L..)..- 10. C. striaas. ll-l2.Matatibraand-rarsus.posterioraspect.-11. C. dotabratus (payi.). - 72. C. \tiatus. ( Different scales for 5-6 lower left ) . 7-U. I I -12 ( lowei right) and 9-10 (upper).

Tab.^l . Head length.inclurling ncct (HL). head width at level of stemmata (HW), length of last abdominal segment (LA-S) and urogomphus (U) in different larval instars of the North European s peciesofColymbetes. Larvae of b. /us- rus from the Netherlands. and those of the other species from northern Sweden. N gives number of larvae measured.

HI- HW LAS t, Instar and specics N SD SD SD SD

First instar dolahratus 5 1.30 .06 t.28 .04 .65 .04 2.01 .10 fuscus 1l 1.22 .08 1.19 .07 .64 .03 1.',70 .17 paykulli 9 1.56 .05 I .54 .03 .89 .05 L72 .10 striatus 8 1.30 .05 1 .26 .06 .72 .05 1.94 .17 Second instar dolabratus 8 2.02 .06 I .93 .03 r.33 .05 2.89 .09 't fuscus 2.1'l .08 2.Ot .06 1 50 .07 2.72 .27 paykulli 7 2.53 .06 2.50 .08 1.83 .10 2.56 .r9 striqtus l0 2.13 .10 2.Ot .08 1.62 .05 2.ffi .11 Third instar dolabratus 7 2.93 .15 2.80 .11 2.36 .17 3.52 .22 fuscus 4 3.3 r .18 3.19 .15 2.62 .15 3.80 .33 paykulli 6 3.71 .21 3.61 .16 3.00 .14 3.44 .29 striatus l1 3.42 .ll 3.24 .08 2.94 .16 3.29 .22 Larvae of North European Colymbetes 97

05.. , , \ \ \\ ,J\ n \ // YE VLlt Figsl3 19. Colymbetes. second-instar larva. l3 l5.Head,dorsal aspect.-13.C.paykulliEr.-14.C'./irscas(L.). 15. C. stnctrrs (L. ). - 1G17. Anterior part of head. vcntral aspect: labium omitted, but first segmeot ofpalpus drawn between mandibles.-16. C. fuscus. -17. C. striauu. - l8-19. Maxilla. vcntral aspcct. - 18. C. fuscus. -19. C. striatus. Different scales for l3-17 (ccntral) and 1tt-19 (right).

mm. Head ventrally brownish with distinct yel- Phenology in most low spots. Outer margin of urogomphus paykulli were specimens with 3 or lers spiniform. yellow setac ln northern Swctlen. larvac of C. (Fig. 30). Temporal spines evidently shortcr than collcctc(l from May to July with most records in secondarv D spincsof protibia and -tarsus ..... Junc. Thc earlicst rccord is ll May 1979 when all three instars were taken together in a bog ditch - l"-l ,,n"tr"r. t *iait ,i".. i..o iliii'" or less. Head ventrally".a testaceous,"i without^ri dis- near Umee (VB). Cenerally, instars I and II ap- tinct colour-pattern. C)uter margin of urogom- pear from late May to early June, and instar III phus in most specimens with 4 or morc from early June to oarly July. Dcviations from this spiniform. yellow setae (Fig. 31). Temporal pattcrn arc causcd by rcgional and interannualdif- spines, at Ieast basally, of about same length as ftrcnces in spring devclopmcnt. Rcsulls from a secondary D spines of protibia and -tarsus . . .. . dolabrotus detailed study of a seasonal t'en in the province 92 Anders N. Nilsson & Jan G. M. Cuppen

l.'l t, ,tt ', ,\ 1, 't ',/ " l' :r' , ,\tl

05mm

Figs 2G25. Colymbetcs, second-instar larva. - 2(l21. Last abdominal segment with urogomphi. - 20. C. poykulli Er. - 21. C. striatus (L.). - 22-23. Metatibia, posterior aspect. - 22. C. paykulli. - 23. C. stiqtus. - 24-25. Metatarsus, anterior aspect, - 24. C. dolobratus (Payk.). - 25. C. striatus. Different scales (each bar 0.5 mm) for 20 21 (lower right).22-23 (lower central). and 24-25 (upper central).

Vasterbotten in 19t17 (Skalan, Skartraskberget), tions of larvae of both species together indicate no based on handnel samples collected at approxi- difference in distribution of instars. mately ten dav intervals during the ice-free season Data on C. dolabratus are more scarce. with the (late April to October), are shown in Tab. 2. As first two instars collected 20 June 1987 at Ammar- this summer was verv rainy, water was present nas (LY) and 8 July 1983 at Tjallingenjaure (AS, during thc wholc summcr. Larvae were prescnt 920 m ASL). Near Abisko (TO), two instar Il lar- only from 31 May to 26 J unc. Thc scasonal occur- vac wcrc collcctcd 28 July 1983, and at Padjelanta rence of larvae of O. striatut at the same site ('fab. (LU) they were collected 13 and 18 July at al- 2) is very similar tothatol C. paykullj, with larvae titudes of 6130 and 5u0 m ASL respectively. Re- present from 7 to 16 June. Dataon C. striatus from cords of instar III are from late June to late July. other northern Swedish localities revealno impor- These observations arc consistent with the data tant differences with respect to larval phenology from Finnish Lapland presented by Eriksson when compared to C. paykulli. Frcqucnl obscrva- ( 1972). As C. dolahratus is more or less confined Larvae of North European Colymbetes 93

."*/ . ! 'l' -. . ': .',i; '.,..'" ' /:.t., . ,: :,',:.-_:'. .; ,r. .'. I ;t,' ' -...... '"'r 'l' \l\,rl1:, :;l': ' ''l"i:it t 27

)\l\ \^J/)

lmm

Figs 26-31. Colymbetes, third-instar larva. -26. C. f*scus (L.), mandible, ventral aspect. -27-28. Head, dorsal as- pect. -27. C. paykulliEr. -28. C. striatus (L.). -29-31. Last abdominal segment with urogomphi.-29. C. paykulli. - 30. C. striatus. - 31. C. tlolabratus (Payk.). Different scales (each bar I .0 mm) for 26 (lower right), /7-28 (upper right), and 29-31 (central).

to high altitudes or latitudes, the larval develop- Data on the phenology of C. /uscas in the ment is generally later in the season with reference Netherlands are given in Fig. 32 for adults and lar- to the main pattern of C. paykulli and C. strialus vae and are based on 221 and ll8 specimens re- described above. However, at Ammarnas C. spectively. All data for the ycars 1974 to 1987 are dolabranu and C. paykulli both had larvae of the pooled; samples werc spread over the whole first two instars on 20 June. country. Adult specimens have been observed 94 Antlers N, NiLssorr & Jan G. M. Cuppen

Tab. 2. Seasonal occurrence of larvae of Colymbetes ( L.) paykulli, C. striqtus, and Rhantirs satrrrel/as in a seasonal fen in northern Sweden (VB: Skatan, Skartraskberget) in 1987. About cvery tcn davs five handnet samples were taken from lnte April lo October. Water temperaturc was measured -5 cm hclow the surface at noon. Larval in- stars 1-3 are given as Ll--j.

May June July Species and instar 31 '7 t6 265

C. paykulli LI L2 t-.1 L:. striatus LI L2 L3 R. sulurellus LI L2 L3 Water temp. .C

throughout the year with an obvious peak in abun- .t F t,l A ttl J J AS 0N 0 dance from August to the first half of October Fig. 32. Scasonal distribution of rccords of adults (top) (Fig. 32). The small gap at the end ofJune and thc and larvae (bottom) of Colvnhetes luscus (L.) in the Ncthcrlands. Pooled data from l97.1to l98Tcoveringthe is a pcriod beginning of July is remarkable for this rvhole countrv given in fortnightly intervals. rvhen much sampling has been done. Also thc rc- latrvely high number of specimens in winlcr. whe n sampling intensity in comparison with March and Apnl was low. is remarkable. Teneral adult spcci- terprctation is corroborated by data on larval and mens have been found in June and mainly July and adult phenology of C. lhscus in the Netherlands August. though numbcrs arc low. (Fig. 32). Here, teneral adults wcrc observed from Compared with thc adults. larvae of C. Juscus Junc to August, and the death of the foregoing have been found onlv during a limited period of gcncration is indicated by the few specimens col- the -""ear (Fig. -12): instar I larvac have been tbund iccted in late June and carly July (Fig. 32). The oc- from March to May: instar lI from April to thc cnd currcnce of larvae in October to December (Fig. of June: and instar III from the second half of 32) suggcsts a flcxibilily of the lite cycle, and prob- April to carly August. Thcrc are also a few obser- ably egg-laying starts already in autumn but is vations of third instar larvae lrom the second half most intense in early spring. Further south, as in of Octobcr to Dcccnrtrcr. Thc main larval period. , the larval development is mainlypassed in howcvcr. lasts fronr April to June. The data for autumn and winter, followed by pupation in thc Nethcrlands arc in accordance with the obser- spring (Bertrand 1928). vations of Galcwski ( 1964) in and Balfour- The data from northern Sweden on C. clola- Browne (19.50) in L.ngland. In France, howcvcr, brotus, C. paykulli aru) (:. striatus largely agrcc Bertrand (1928) found larvac throughout tlrc with C. frscas in thc Ncthcrlands except that vear. but mainlv in ilutr.rrnn ard r\ inler. hrccding and larval dcvclopment are about two months later in the season. However. the longer winter at higher latitudes in combination with the Life hislon Iemporary character of most breeding pools could Both Galewski (196:l) and James (1970) suggested make a univoltine life cycle impossible. iviost that the lite cycle ol (-olynthetes isunivoltine. with often, the breeding pools arc dry at the time of larval devclopnrent in spring or early summcr and adult cmergence, and pools arc subsequently fil- overwintering adults only. Gencrally, this in- lcd with water at most for a very short period in au- Larvae of North European Colymbetes 95 tumn when food is scarce (Nilsson 1986b). In this Acknowledgemenls: We thank Ms L. Bondestad and Mr young situation it is difficult to understand how the adults V. Jussila, Umed. for valuable help in obtaining larvae of C. dolabrqtus. Ms E. Engblom and Mr P.-E. manage to feed and mate before they breed in Lingdcll, Tyresd. provided us with larvae oI C. dola- early spring next year. Most probably. as hratur from northcrn Swedcn and Greenland. Mr R. suggested by James (1970) and Galewski (1971), Carr, Maidstone, and Dr G. N. Foster, Prestwick. emerging adults migrate to more permanent wat- kindly senr us larvae of C. /rs.as from England. Dr D. J. Larson, St. John's, helped us improve the manuscript. ers where they stay during winter. Following this ecological strategy, they belong to the "non-win- tering spring migrants" of Wiggins et al. (1980). It should be emphasized, that the data at hand from References northern Sweden cannot reject the possibility of a Balfour-Browne- F. 1950. British Water . Vol. 2. semivoltine life cycle. This pattern would emerge Ray Socicty, London. 394 pp. if the new adult generations stay in or near the Bcrtrand, H. 1928. Lcs larvcs ct nymphes des Dyti- scides. Hygrobiides et Haliplidcs. Encycl. ent. l0: pools where they have developed. In this case they 1-366. - probably would have to feed and mate their first Eriksson, U. 1972. 1'he invertebrate fauna ofthe Kilpis- spring, and delay their egg deposition to the fol- jiirvi area, Finnish Lapland. 10. Dytiscidae. - Acta lowing spring. A semivoltine life cycle seems Soc. Fauna Flora fenn. 80: 12l-160. Galcwski. K. 196.1. Immature stages of the Central necessary for C- dolabratus as in the arctic adults Europcan specics of Colvmbctcs Clairvillc (Coleo- have bcen collectetl in pools of water on pack ice ptera, Dytiscidae). Annls zool. Warsz. 2?: 23-55 - (Zimmerman l98l). Oalewski. K. 1967. The- description of pupae of Colym- In ordcr to cstablish the voltinism displayed by betes paykulli Er. and C. dolabratus (Payk.) with a key to the identification of pupae of the European Colymbetes specics at different latitudes, more at- specics of Colymbctes Clairv. (Coleoptera, Dyti- tcntion must bc paycd to ovarian development scidae). Annls zool. Warsz. 24:367-374. and egg-laying bchaviour. Galcwski. K.- 1968. Thc dcscriptions of larvae of Colym- Observations of C. paykulli and C. striatus in betes dolabratus (Payk.) with keys to the identifica- tion of larvae ofthe European species of Colymbetes northern Sweden indicate larvae feed that the Clairv. (Coleoptera. Dytiscidae). Annls zool. mainly on thc larvac and pupae of Aedes mos- lNarsz.26:.227-238. - quitocs. At thc timc of cmcrgencc of the Colym- Galcwski, K. 1971. A study on morphobiotic adapta- betes larvac, thc Aedes larvae havc gencrally tions of Europcan spccics of thc Dytiscidae (Colco- ptera). .._ Polskie Pismo Ent. 4l:.487--702. reached thcir third or fourth instar, and the larvac James. H. G. 1970. lmmature stages of five diving bee- of the egg-overwintering Agabus species, thc tles (Coleoptera: Dytiscidae), notes on their habits other important exploiters of this prey, arc about and life history, and a key to aquatic beeiles ofvernal ready for pupation. Galewski (1964) noted that in woodland pools in southcrn Ontario. Proc. ent. Soc. Ont. 100: 52-97. - Poland the larval development genera of the Col- Nilsson, A. N. 1982. A kcy k) thc larvae of thc Fcnno- ymbetes and Rhantus was separated in time, with scandian Dytiscidae (Coleoptera). Fauna Norr- that of Rhantus later in the season. This is also landica, UmeA 1982 (2\: 145. - generally the case in the Netherlands (Cuppen, Nilsson, A. N. 1986a. Life cycles and habitats of the northern European Agabini (Coleoptera: Dyti- unpublished). However, in northern Sweden, the scidc). Entomol. Basiliensia I l; 391-417. species R. suturellus (Harris) often co-exists with Nilsson, A.- N. 1986h. Community structure in the Dyti- C. paykulli and/or C. striatus. ln this case the lar- scidae (Colcoptcra) of a northcrn Swedish seasonal 23: val dcvelopmcnt of the two genera shows a consid- pond. Ann. zool. fcnnici 39-47. Nilsson, A.- N. 1987. Thc larva of Rhantus fennicus (Co- pond in erable overlap, and in the referred to Tab. leoptera, Dytiscidae), with a kcy to thc Fcnnoscan- 2, Iarvae of R. suturellus occ\rred from 6June and dian species of Rhantus. Notul. ent . 6'7: 3341 . onwards. Stiderstrom, O. & Nilsson, -A. N. 1987. Do nymphs of Nilsson (1986b) stated that in a seasonal pond, Parameletus chelifer and P. minor (Ephemeroptera) reduce moriality from predation by occupying tem- larvae C. paykulli the of fed mainly on mayfly lar- porary habitats'l Oecologia (Berlin) 7413946. vac. However, when re-examined these larvae in- Wiggins, G. 8., Mackay,- R. J. & Smith. I. M. 1980. El'- clude both C. paykulli and, predominantly, C. olutionary and ecological strategies of in an- striatrer. Feeding experiments indicated that mos- nual temporary pools. - Arch. Hydrobiol. Suppl. quito 58:97-206. larvae and mayfly larvae are consumed at Zimmerman, J. R. 1981. A revision of the Colymbetes equal rates when served together (SOderstrom & of North America (Dytiscidae). Coleopt's Bull. Nilsson 1987). 35: l-52. - 96 Anders N. Nilsson & Jan G. M. Cuppen

Sammanfattning De fyra nordeuropeiska Colymbetes-arternas Vidare redovisas arternas fenologi i norra Sverige larver har tidigare ej kunnat artbestemmas m h a och Nederlinderna. Arternas livscykler disku- tillganglig litteratur. Speciellt har larven till C. teras. Ylterligare studier er nddvendiga for atl puykulliErichson varit okiind. I dcnna uppsats gcs avgtira om och under vilka fcirhillandcn livscykeln cn bcstamningstabcll till alla fyra arternas tre ar ctt- ellcr tv6-irig. larvstadier. och flcra nya karakliircr prcscntcras.

Recension Lucht. W. H. 1987. Die Kiilbr Mitteleuropas. - trots att ju arten saknas i det innefattade omr&- Katalog. Gocckc & Evcrs Verlag. Krefeld. ISBN det. Istallet saknas i katalogen Laccophilus stroeh- 3-87263-035-(1. 342 s. Pris Il2 DEM. rri som ju faktiskt tdrekommer i Bohuslin och diirmed i Sydsverige. Arter vilka i ett omrade en- Denna centraleuropeiska skalbaggskatalog iir ut- dast har petriiffats f