MEx. 70 ( 1986) nte delimitada por dos abruptos pro­ TERRITORIAL BEHAVIOR OF THE SUBSOCIAL a transversal que es medida no está HELISCUS TROPICUS UNDER LABORATORY de prominencia (figs. 9 y 14). En S. CONDITIONS (COLEOPTERA, ) :mcavidad central del borde postero­ ' menos profunda y lateralmente está nares sin embargo la placa transver­ ¡ueada por dos abruptas prominencias

,, neto, en relación con la ausencia de

JORGE V ALENZUELA-GONZÁLEZ

lENTOS Centro de Investigaciones Ecológicas del Sureste nstituciones por el' préstamo de mate­ Apartado Postal 36 Dr Randall T. Schuh (AMNH); Dr. Tapachula, Chiapas 30700 ra. Ursula Gollner-Scheiding (ZMB); MEXICO 1mann (MABR); Dr. Abraham Wil­ 'A); Al Dr. W. R. Dolling (BMNH) >rindados en el curso de este estudio. ional de Ciencia y Tecnología (CO permitió visitar diversos museos sud- al M. en C. Pedro Reyes-Castillo y >ermitirme trabajar durante mi año ' de Ecología, A. C.

CITADA

eteropterorum Bruxellensis 11. Coreidae, 'em. S oc. Entamo/. Belgique. 22: 154-155. ae in the Rijksmuseum van Natuurlijke Meded. 18:187. 'ntius St

1 1' Academie Royal e de Belgique: 85 ~venska Vet. Ak. Handl 12:181-192. Ofv. Vet-Ak. Fort. 16(10) :471-472. Folia Entomológica Mexicana No. 70: 53-63 (1986) ,K. Svensksa Vet-Ak. H andl. 9 (1) : 207. of Hemiptera-Heteroptera in the collec­ l: 103 y 142-143. Recibido para publicación: 20 enero 1986. Aceptado para publicación: 26 mayo 1986. 53 54 FoLIA ENTOMOL. MEx. 70 ( 1986) VALENZ

zation, which occurs in dec< together and cooperate in th .After their eclosion, the you help their progenitors with later they disperse and form 1 Castillo, 1975; Schuster 197 RESUMEN González & Castillo, 1984; 1985) Generally these : El comportamiento territorial de H. tropicus, su variación estacional y la part1c1pa­ Gray, 1946; Schusted 1975:: ción de cada uno de los sexos en dicho comportamiento fueron estudiados por medio Sorne observations carried de la introducción de pasalidos "extraños" en nidos huéspedes instalados en el labora­ torio. Se encontró que únicamente los nidos colectados en la época de reproducción suggest the existence of a se: presentan este comportamiento. Este se manifiesta por medio de la producción de reac­ junctus (Illiger). Other stU< ciones agonísticas ostensibles (embestidas, mordidas y huidas) al contacto entre los Schuster ( 1975a) with the sa huéspedes y los intrusos. En todos los casos observados los huéspedes iniciaron la agre­ sión y los intrusos presentaron un comportamiento de huida. La mayor parte de estas affinis ( Percheron), also su¡ interacciones fueron unidireccionales (de los huéspedes a los intrusos) ; sin embargo, species. N evertheless, in all 1 ocasionalmente, se observaron también algunas interacciones agonísticas recíprocas que sional. In previous publicati tuvieron el mismo resultado que las anteriores. Ambos sexos participan en la defensa del nido, pero la agresión es más frecuentemente dirigida hacia los individuos del mismo productive behaviour (Valen: sexo. También se observó que algunos de los intrusos pueden ser tolerados por las pa­ lenzuela-González, 1985) of 1 rejas territoriales; con los datos disponibles no es posible explicar el origen de estas to the tribe Proculini and variaciones en el comportamiento. present study we report th PALABRAS CLAVE: Comportamiento Territorial, Passalidae, Insectos subsociales, carried out under laboratory México. torial behaviour of these im sex in this same behaviour. ARSTRACT

Territorial behavior, its seasonal variation and the partJc1pation of each sex were studied in H. tropicus by introducing "foreign" passalids into host nests imtalled in the laboratory. Only nests collected in the reproductive season exhibited this behaviour, The were collecte' which comprises obvious agonistic reaction ( attacks, bites and retreats on contact be­ of Berriozabal, Chiapas, Me tween the host and intruders. In all observed cases the hosts initiated the aggression and type of nests utilized for thc intruders presented the escape response. The majority of these interactions were uni­ directional (from host to intruder), but occasionally sorne reciproca! agonistic interac­ described ( Valenzuela-Gonz: ctions were observed that nevertheless had the same end result. Both sexes participated With the object of studying in nest defense but aggression was more frequently directed at individuals of the same­ sects, a series of experimenl sex. It was also observed that sorne intruders were tolerated by the host pair; with the data available it is not possible to explain the origin of this variation in behaviour. were introduced into host r nests were occupied by pass KEY WORDS: Territorial behaviour, Passalidae, Subsocial Insects, Mexico. so that there was no modifi was also utilised for the ex¡: lNTRODUCTION After their installation in in complete darkness to allc Passalids are saproxylophagous subsocial (Wilson, 1971). The repro­ roundings. Following this p ductive unit begins with the formation of a monogamous pair; aftcr fertili- were started using individm ( 1986) VALENZUELA. BEHAVIOR OF Heliscus 55

zation, which occurs in decaying tree trunks, both members of the pair stay together and cooperate in the construction of galleries and care of the young. After their eclosion, the young adults remain for sorne time in the nest and help their progenitors with the care of the younger members of the brood; la ter they disperse and form new nests ( Ohaus, 1900, 1909; Gray, 1946; Reyes­ Castillo, 1975; Schuster 1975a; Reyes-Castillo & Halffter, 1983; Valenzuela­ González & Castillo, 1984; Valenzuela-González 1985; Schuster & Schuster 1985) Generally these insects have a seasonal life-cycle ( Pearse et al.) 1936; .."''""'u" estacional y la participa­ Gray, 1946; Schusted 1975a; Valenzuela-González, 1985). estudiados por medio instalados en el labora­ Sorne observations carried out by Gray ( 1946) and Mullen & Hunter ( 1973), en la época de reproducción suggest the existence of a seasonal territorial behaviour in dis­ medio de la producción de reac­ junctus (Illiger). Other studies varried out by Alexander et al. ( 1963) and y huidas) al contacto entre los los huéspedes iniciaron la agre­ Schuster (1975a) with the same species and by the latter author with Passalus huida. La mayor parte de estas affinis ( Percheron), also support the existen ce of this behaviour in the two a los intrusos) ; sin embargo, species. Nevertheless, in al! these cases the observations were scant and occa­ agonísticas recíprocas que sexos participan en la defensa sional. In previous publications we have reported various aspects of the re­ hacia los individuos del mismo productive behaviour (Valenzuela-Rodríguez & Castillo, 1984) and biology (Va­ lenzuela-González, 1985) of Heliscus tropicus (Percheron), a passalid belonging to the tribe Proculini and having a wide distribution in Mexico. In the present study we report the results obtained from a series of experiments Passalidae, Insectos subsociales, carried out under laboratory conditions with the object of studying the terri­ torial behaviour of these insects, its seasonal variability and the role of each sex in this same behaviour.

METHODS part1c1pation of each sex were into host nests installed in the The insects were collected in "El Suspiro", a locality in the municaplity of Berriozabal, Chiapas, Mexico. The location, techniques of collection and type of nests utilized for the observations of the insects have been previously reciproca! agonistic interac­ described (Valenzuela-González & Castillo, 1984; Valenzuela-González 1985). Both sexes participa ted With the object of studying the existence of territorial behaviour in these in­ at individuals of the same­ sects, a series of experiments was carried out where "instrusive" individuals by the host pair; with the of this variation in behaviour. were introduced into host nests previously installed in the laboratory. These nests were occupied by passalids al! collected from the same nest in the field Insects, Mexico. so that there was no modification of the host group. The original nest wood was also utilised for the experiments. After their installation in the laboratory, the insects remained for five days in complete darkness to allow them to become accustomed to their new sur­ roundings. Following this period, the homospecific introduction experiments pair; after fertili- were started using individuals collected at the same time and place as those 56 FoLIA ENTOMOL. MEx. 70 (1986) VALENZl from the host nest. Thus insects of unknown age were used, although to reduce the influence of this factor only individuals that had aquired adult colour were utilized. Typically, with this species the adults attain their characteristic 1) Description of behavio black colour at approximately four months. ( 21.6%) aggressive interactio During the agonistic interactions between passalids, obvious acts physical initiated the aggression and 1 aggression such as attacks and hites were seen, although usually accompanied escape response to the aggre: by other acts including exploratory movements, antennal tapping and stri­ these encounters were marke dulations (Gray, 1946; Alexander et at., 1963; Mullen & Hunter, 1973; Schus­ sistence of the aggression, it ü ter, 1975a; Valenzuela-González & Castillo, 1984). However, these latter acts finity in the host nest the fin; al so manifest themselves in other situations ( Alexander et al., 1963; Schuster, der, principally due to the 1975a, b; Buchler et al., 1981; Valenzuela-González & Castillo, 1984). For this thcse insects possess ( Reyes-C reason, to study territorial behaviour, the criteria used for the existence of The behaviour observed ' aggressive behaviour were the presence of attacks, hites and escapes ( the rapid Alexander et al. ( 1963) anc withdrawal of the attacked individual). When this type of interaction between (Figure 1). The stimulus th< host and intruder was not seen during an observation period of 30 minutes blishment of contact with ti­ after initial contact between the two, the intrusions were considered to be to one another but without tolerated by the host nest. In such cases of tolerance, three other similar in­ aggressive behaviour manifes traductions with different individuals were carried out, each with an inter­ and tapping is performed O\ vening periodo of 24 hours. If after these four trials no territorial behaviour were observed in every eno was observed, it was considered to be absent from the nest in question. With heard but coul not be verifiec the object of studying thc possible seasonal variation in the behaviour, two not audible. On one occassi groups of insects were studied. One group consisting of pairs of passalids col­ also noted which was similar lected from July to October (n=28), during the hegiht of the breeding lenzuela-González and Castill season, the other group being passalids collected from February to May Once initiated, the aggres (n=23), when the reproduction of H. tropicus had ceased in the area (Va­ During the attacks, the aggre lenzuela-González, 1985). its mandibles, apparently tryi As these insects display no externa] and in order to so that it might then, on s differentiate the reactions of each member of the pair and the influence of the During these attacks the ins sex of the intruder, a series of tests were carried out with marked passalids. bite on contact with one an The technique for marking is described in Fresneau & Charpin ( 1977). Four cuticle and because the maj intruder introduction tests were carried out in each nest, two with males and or abdomen of the rival, th1 two with females. Intruders were scxed by anesthetizing (with C02) opening to a leg or , the str the pygidial plate and observing the presence of abscence of an edeaguous with severa! seconds) could be suf a microscope. During sexing, they were handled very carefully to avoid any sions we observed that duri possible injury. Hosts were sexed in the same way, but after theend of the passalid by the bitten appe experiments. These experiments were varried out withan interval of 24 hours against the walls of the galler between each tria!, alternating between males and females. With respect to During these interactions 1 the eight nests utilised as hosts for thesc tests, only those containing indivi­ position similar to that desc1 duals that had previously demostrated agonistic behaviour were used. junctus as "submission". In t rally with respect to the oth \!ALE N ZUELA. BEHAVIOR OF H eliscus 57

used, although to reduce RESULTS had aquired adult colour attain their characteristic 1) Dcscription of behaviour. Of the 51 experiments performed, in 11 cases (21.6'/o) aggressive interactions were recorded. In each case the host insects obvious acts physical initiated the aggression and were victorious, with the intruders presenting an usually accompanied escape response to the aggression. The agonistic interactions observed during tapping and stri- these encounters were markedly "violent". Because of the intensity and per­ & Hunter, 1973; Schus­ sistence of the aggression, it is probably that if the introdus had been left inde­ However, these latter acts finity in the host nest the final result would have been the death of the intru­ et al., 1963; Schuster, der, principally due to the hites inflicted by the powerful mandibles that & Castillo, 1984). For this these insects possess (Reyes-Castillo & Jarman 1981 ). used for the existence of The behaviour observed was similar to that described by Gray ( 1946), and escapes ( the rapid Alexander et al. ( 1963) and Schuster ( 1975a) in Odontotaenius disjunctus of interaction between (Figure 1). The stimulus that seems to trigger of the aggression is the esta­ period of 30 minutes blishment of contact with the intruder. The insects may aproach very close were considcred to be to one another but without contact no reaction is apparent. Befare directly aggressive behaviour manifests itself (attacks and hites), antennal exploration out, each with an inter­ and tapping is performed over the body of the other individual. These acts no territorial behaviour were observed in every encounter ( n=45). Usually werc also the nest in question. With heard but coul not be verified in al! cases and possibly in sorne cases they were in the behaviour, two not audible. On one occassion bcfore aggression, a rotation behaviour was of pairs of passalids col­ also noted which was similar to that present during courtship behaviour (\la­ hegiht of the breeding lenzuela-González and Castillo 1984). from February to May Once initiated, the aggressive interactions were mainly attacks and hites. ceased in the area (\la- During the attacks, the aggressor passalid continually pushed and its rival with its mandibles, apparently trying to locate them under the body of its opponent and in arder to so that it might then, on suddenly lifting its read, overturn its opponent. and the influence of the During these attacks the insects would keep the mandibles opcn and try to bite on contact with one another. However, because of the hardness of the cuticle and because the majority of the attacks took place over the thorax nest, two with males and or abdomen of the rival, the hites were rarely serious. Nevertheless, applied

(with C02) opening to a leg or antenna, the strength and duration of a bite ( of thc order of of an edeaguous with severa! seconds) could be sufficient to sever the appendage. On severa! occa­ carefully to avoid any sions we observed that during the hites the aggressor "carried" the other but after theend of the passalid by the bitten appendage, generally a leg, and pushed it violently interval of 24 hours against the walls of thc gallery where the latter managed to escape (Figs. 1-4). During these interactions the recipients of aggression frequently adopted a ~ly those containing indivi­ position similar to that described by Mullen and Huntcr (1973) for O. dis­ ~haviour were used. junctus as "submission". In these cases the attacked passalid placed itself late­ rally with respect to the other, hiding its ipsilateral legs and antenna under 58 FoLIA ENTOMOL. MEx. 70 ( 1986) VALEN

its body, sucho that it low same the contralateral legs of the gallery. Thanks to t bite the rival's appendages nated with the rapid retrea with the host insect, the ag In the ma jority of the cas sion. However, on two oce< blished an aggresive inter2 tion was 4 minutes and 25 with the intruders retreatin probable that this type of from the nest as in the ca~ present experiment interact the inserts could not flee; the observed interactions.

2) A study of territoriali season. In none of the 2: could we confirm the presf used. On the contrary, of (39.3%) of agonistic reacti1 gest that territorial behavio' it is worth mentioning that firmed, in four of these \\ between the host pair. In pairs of Prorulejus sp. anc to copulate under laborat< 3 intruders provoked immed bed above.

3) A study of territoriali ders. Table 1 shows the res1 scxes can participate in the 4 more frequent aggression t' Figs. 1-4. Aggresive interactions in Heliscus tropicus. 1) frontal assault; 2) lateral 0.001); similarity, female h< assault, with "submission" position of the attacked beetle; 3) lateral assault with the 2 aggresor overturn its opponent; 4) aggressor carring the opponent by the bitten leg. truders than to males (X .= two intrudes ( females in b< tic reaction on the part of f ( 1986) VALENZUELA. BEHAVIOR OF Heliscus 59

its body, sucho that it lowered this side to the leve! of the ground. At the same the contralateral legs remained firmly attached to the ground or walls of the gallery. Thanks to this adopted stance, the aggressor could not easily bite the rival's appendages nor easily overturn it. Al! these interactions termi­ nated with the rapid retreat of the intruder; if the latter restablished contact with the host insect, the aggressive behaviour would immediately begin again. In the majority of the cases only one of the insects ( the host) showed aggres· sion. Ilowever, on two occasions the intruders responded to attacks and esta­ blished an aggresive interaction. The longest duration of such an interac­ tion was 4 minutes and 25 secons. The passalid hosts were always the victors with the intruders retreating at the end of combat. In the natural state it 1s probable that this type of encounter finishes with the exit of the intruder from the nest as in the cases reported by Schuster ( 1975a). However in the present experiment interactions were carried out in a closed nest from which the insects could not flee; this fact might explain in part the "violence" of the observed interactions.

2) A study o( territoriality in nests collected during and after the breeding season. In none of the 23 nests collected outside the reproductive period could we confirm the presence of territorial behaviour towards the intruders used. On the contrary, of the 28 nests in a reproductive phase, 11 cases (39.3%) of agonistic reactions to intruders were observed. These results sug­ gest that territorial behaviour is closely linked to reproduction. In this respect it is worth mentioning that of the 11 nests in which this behaviour was con­ firmed, in four of these we observed courtship and in one case copulation between the host pair. In addition we carried out similar experiments with pairs of Proculejus sp. and Spurius bicornis (Truqui) which were observed to copulate under laboratory conditions. The introduction of homospecific intruders provoked immediate agonistic interactions similar to trose bescri­ bed above.

3) A study of territoriality as a function o( the sex o( the host and intru­ ders. Table 1 shows the results obtained and indicates that individuals of both sexes can participate in the defence of the nest. Nevertheless the males showed more frequent aggression to maJe intruders than to females (X2=6.8; p < ~- 1) frontal assault; 2) lateral 0.001); similarity, female hosts showed more frequent aggression to female in­ ~tle; 3) lateral assault with the truders than to males (X~=4.5; p 0.05). It is interesting to note that only ie opponent by the bitten leg. < two intrudes ( females in both cases) were observed that provoked no agonis­ tic reaction on the part of either of the hosts, in al! eight tests. 60 FoLIA ENTOMOL. MEx. 70 ( 1986) VALE!

TABLE 1 tions carried out by Gra) modifications in reproduct The number of times that males and females of territorial pairs of H. tropicus our own observations indi, reacted ( +) or did not react (-) agonistically to homospecific intruders of zuela-González, 1984). both sexes in their nests and percentage of positive reactions The experimental data ! theless the aggression sho.,. Hosts Intruders (+) (-) % an intruder of the same seJ mon in insects ( see review: o 'i' 14 2 87.5 lington, 1983). Cases are kJ 'i' 'i' 12 4 75 ki, 1933; Milne & Milne, J o o 7 9 43.7 ( Seelinger and Seelinger, 'i' o 5 11 31.1 the passalids, with the ins' 11 31.3 of the same sex. Nevertheless, in the cast of both sexes sometimes di In fact there can be great DISCUSSION cases both male and femal1 ner is thus disposed (Vale The existence of aggressive behaviour towards intruders, plus the fact that only eight nests it is diffiet in al! observed cases i~ is the host that initiates this aggression and the intru­ viour of the male and ferr ders who retreats, togcther indicate the presence of territorial behaviour in could not study, such as agt these insects. Mereover, our results confirm the observations of Gray ( 1946) cal state (as well as that e and Mullen & Hunder ( 1973) in that there exist seasonal variations in the the nest, the "cohesion" oJ territorial behaviour of these insects which is closely linked to the reproduc­ this variation. tive period. The biology of the passalids suggests the existence of a strong Moreover, during these selection pressure at the leve! of pair and nest defence. In effect these insects that did not trigger off ag( form monogramous pairs with both partners exhibiting parental care (Schus­ the collection of nests of r ter, 1975a; Reyes-Castillo & Halffter, 1983; Valenzuela-González, 1984); pair of occupants was er they have a sex ratio of 1:1 (Gray, 1946; Valenzuela-González, 1985), a life adults were found. Similar cycle that is seasonal ( at least in sorne species such as ll. tropicus) and invest been reported in other terr considerable of time and energy in nest construction prior to mating (Gray, that territorial males of th1 1946; Schuster, 197 5a; Reyes-Castillo & Halffter, 1983; Valenzuela -González ve" males within their terr & Castillo, 1984; Valenzuela-González 1985). tely repulsed. Possibly thi The abundance of food once located, together with the characteristics of insects that do not repre~ the biology of those insects previously mentioned, might explain the seasonal pair, could facilitate cons1 variations in territorial behaviour. Nevertheless it is important to consider the brood, since the Iarvae der fact that it was only possible to confirm this behaviour in a proportion of ]arman 1981, Reyes-Castil reproductive pairs. We can not exclude the possibility that this type of varia­ cessary to carry out compl tion is also seen in the natural state; however it is also possible that it is due to understand the factors t to stress produced by their collection and location in the laboratory. Observa- ~986) VALENZUELA. BEHAVIOR OF Heliscus 61

tions carried out by Gray ( 1946) on O. disjunctus, suggest that important í modifications in reproductive behaviour can occur following their collection; iritorial pairs of H. tropicus our own observations indicate a similar phenomenon in H. tropicus (Valen­ ~ homospecific intruders of zuela-González, 1984). ~ positive reactions The experimental data show that both sexes display this behaviour. Never­ 1 ! theless the aggression shown by each sex is more frcquently directed towards (-) % an intruder of the same sex. Territorial defence by both sexes is not very com­ mon in insects (see reviews by Price, 1975; Baker, 1983; Fitzpatrick and Wel­ 2 87.5 lington, 1983). Cases are known in silphids of the genus Necrophorus (Pukows­ 4 75 ki, 1933; Milne & Milne, 1976) and in cockroaches of the genus Cryptocercus 9 43.7 (Seelinger and Seelinger, 1983). Both cases presented a similar situation to 11 31.1 the passalids, with the insects displaying aggression principally to individuals 11 31.3 of the same sex. Nevertheless, in the case of H. tropicus, we also observed that individuals of both sexes sometimes displayed aggression to members of the opposite sex. In fact there can be great variability between one nest and another: in sorne cases both male and female are very aggressive, while in others only one part­ ner is thus disposed (Valenzuela-González & Castillo, 1940). With data from truders, plus the fact that only eight nests it is difficult to explain the origin of these variations in beha­ aggression and the intru­ viour of the male and female hosts. The influence of various factors that we of territorial behaviour in could not study, such as age of intruders, strength of pair bond, their physiologi­ servations of Gray ( 1946) cal state (as well as that of the hosts), the presence or absence of a brood in seasonal variations in the the nest, the "cohesion" of thc host pair, etc., might be a source of sorne of ly linked to the reproduc- this variation. the existence of a strong Moreover, during these experiments we observed sorne cases of intruders nce. In effect these insects that did not trigger off agonistic reactions from the hosts. In the field during hing parental care (Schus­ the collection of nests of reproducing pairs, in the mejority of cases a single ~lenzuela-González, 1984); pair of occupants was encountered; however, occasionally more than two ~ela-González, 1985), a life adults were found. Similar cases, of tolerance towards certain individuals, has 1 as H. tropicus) and invest been reported in other territorial insects. For example, Ewing ( 1972) observed ~n prior to mating (Gray, that territorial males of the cockroach Nauphotea cinerea tolerate " submissi­ 11983; Valenzuela -González ve" males within their territory, whereas other territorials males are immedia­ tely repulsed. Possibly this tolerance towards other individuals (probably with the characteristics of insects that do not represent sexual competitors to the hosts) by the nest might explain the seasonal pair, could facilitate construction of galleries and food production for the J important to consider the brood, since the larvae depend on the adults for their food (Reyes-Castillo & ~aviour in a proportion of ]arman 1981, Reyes-Castillo & Halffter 1983). Nevertheless it would be ne­ 'ity that this type of varia­ cessary to carry out complementary studies about these interactions in order also possible that it is due to understand the factors that regulate them. in the laboratory. Observa- 62 FoLIA ENTOMOL. MEx. 70 ( 1986) VALENZl

AcKNOWLEDGEMENTS ScHUSTER, J. C. 1975b. A com¡ new position for beetles. Cale ScHUSTER. J. C. AND L. B. Sci I am very greateful to M. en C. Pedro Reyes-Castillo from the Instituto leoptera: Passalidae) : Coope de Ecología for his continua! helpful discussions during this work and to Dr. SEELINGER, G. AND U. SEELINGE in the primitive cockroach C1 Guillermo !barra from CIES for critica! review of the manuscript. I also 315-333. thank Dr. Peter Baker from CIES for his comments and help with the VALENZUELA-GONzÁLEZ, J. y ~ translation of the papel and Mrs. Alvaro García-Ballinas, Antonio López• y cópula en Heliscus tropicu 73-92. Yléndez and Miguel Pérez Bautista for their assistence during the collection VALENZUELA-GONZÁLEZ, J. 198 of the insects. in a tropical locality in southe WILSON, E. O. 1971. The Insec

REFERENCES

ALEXANDER, R. D., T. E. MooRE AND R. E. WooDRUFF. 1963. The evolutionary dif­ ferentiation of stridulatory signals in beetles (Insecta, Coleoptera). Behaviour. 11:111-115. BAKER, R. R. 1983. lnsect territoria1ity. Ann. Rev. Entomol. 28:65-89. BucHLER, E. R., T. B. WRIGHT AND E. D. BROWN. On the functions of stridu1ation by the Passalid beetle Odontotaenius disjunctus ( Coleoptera: Passalidae). Animal Beha­ viour. 29:483-486. Ewing, L. S. 1972. Hierarchy and its relation to territory in the cockroach Nauphotea cinerea. Behaviour. 42:152-174. FITZPATRICK, S. M. AND W. G. WELLINGTON. 1983. lnsect Territoriality. Can. ]. Zool. 61 :471-·HHi. FRESNEAU, D. A. AND A. CHARPIN. 1977. Une solution photograhphique au probleme du marquage individue! des pctites insectes. Ann. S oc. Ent. Franc. 13: +23-426. GRAY, l. E. 1946. Observations on the life history of the horned Passalus. Amer. Midl. Nat. 35:728-746. MII.NE, L. J. AND M. MILNE. 1976. The social behavior of burying beetles. Sci. Amer. 235:84-89. MuLLEN, V. l. AND P. E. HuNTER. 1973. Social behavior in confined populations of the horned passalus beetle (Coleoptera, Passalidae). ]. Georgia Entomol. So c. 8: 115-123. ÜHAus, F. 1900. Bericht uber eine entomologische reise nach Central Brasilien. Stett. Entomol. Zeit. 61: 164-173. ÜHAUS, F. 1909. Bericht uber eine entomologischc studenreise in Sudamcrica. Stett. Entomol. Zeit. 7: 1-39. PEARSE, A. S., M. T. PATTERSNO, J. S. RANKIN AND G. D. WHARTON. 1936. The eco­ logy of Passalus cornutus a beetle which live in rotting logs. Ecol. Monogr. 6:+55-490. PRICE, P. W. 1975. Insect Ecology. Wiley, N. Y. PUKOWSKY, E. 1933. Oekologische Untersuchungen an Necrophorus F. Zeit. }vforph. Oekol. 2 7:518-586. REYES-CASTILLO, P. AND G. HALFFTER. 1983. La structure sociale chez les Passalides. Bull. Soc. Ent. France. 88:619-635. REYEs-CASTILLO, P. Y M. ]ARMAN. 1981. Estudio comparativo de la fuerza ejercida por las mandíbulas de y adulto de Passalidae (Coleoptera: Lamellicornia). Folia Entamo[. Mex. 48:97-99. REYES-CASTILLO, P. 1975. El comportamiento social de los Pasalidos. Folia Entomol. M~x. 33:74-75. ScHUSTER, J. C. 1975a. Comparative behavior, acoustical signals and ecology of New World Passalidae (Coleoptera). Ph. D. Dissertation, University of Florida. \ '

VALENZUELA. BEHAVIOR OF Heliscus 63

ScHUSTER, J. C. 1975b. A comparative study of copulation in Passalidae (Coleoptera); new position for beetles. Coleo p. Bull. 29:75-81. ScHUSTER. J. C. AND L. B. ScHUSTER. 1985. Social Behavior in Passalid beetles (Co­ from the Instituto leoptera: Passalidae) : Cooperative brood care. Florida Entomologist. 68:266-272. SEELINGER, G. AND U. SEELINGER. 1983. On the social organization, alarm and fighting in the primitive cockroach Cryptocercus punctulatus SCUDER. Z. Tierpsychol. 61: the manuscript. I also 315-333. and help with the VALENZUELA-GONzÁLEZ, J. Y M. L. CASTILLO. 1974. El comportamiento de cortejo Antonio López• y cópula en Heliscus tropicus (Coleoptera, Passalidae). Folia Entomol. Mex. 61: 73-92. during the collection VALENZUELA-GONZÁLEZ, J. 1986. Life cycle of the subsocial beetle Heliscus tropicus in a tropical locality in southern Mexico. Folia Entamo[. Mex. 68:41-51. WILSON, E. O. 1971. The Insect Societies. Harvard University Press.

1963. The evolutionary dif­ lniPm1tPr.). Animal Behaviour.

functions of strid u la tion by : Passalidae). Animal Beha-

the cockroach Nauphotea

Territoriality. Can. J.

au probleme 13:423-426.

burying beetles. Sci. Amer.

in confined populations of Georgia Entorno/. S oc. 8:

Central Brasilien. Stett.

in Sudamerica. Stett.

fuerza ejercida Lamellicornia) .

Folia Entamo[.

and ecology of N ew of Florida.