Expulsion and consumption of male ejaculates by promiscous female Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae)

While expulsion of male ejaculates by the females after copulation has been reported for various animal groups, expulsion followed by consumption of the expelled ejaculate is a rare behaviour outside spermatophylax-producing orthopterans. Among Diptera, this behaviour has been reported for a few species of Piophilidae, Empididae and Ulidiidae. Here we report on its occurrence among Euxesta eluta and Euxesta mazorca (Diptera: Ulidiidae). We also attempt to characterize the mating system of E. eluta in order to facilitate future hypothesis testing to understand the behavioural factors leading to the evolution of this peculiar behaviour. For this, courtship sequences, copulation duration, frequency of ejaculate expulsion and subsequent consumption, and latency to ejaculate expulsion for both E. eluta and E. mazorca were recorded. The time of sexual maturation, the time window of sexual receptivity during the day, and the mating frequency and variance in mating success for males and females (degree of polygamy) were determined for E. eluta. Both E. eluta and E. mazorca males engaged in elaborate courtship sequences involving visual and tactile displays before copulation. Females of both species almost invariably expelled and consumed ejaculates after copulation. Female E. eluta, required a 6- to 9-day period feeding on protein and sugar before becoming sexually receptive. Reproductive activity occurred continuously over the day with an early morning and late afternoon peak. Both males and females could mate multiply, with multiple partners over a 2-h observational period. Sexual network analysis revealed that some males and females had greater mating success than others. Ejaculate consumption appears to be widespread in the genus Euxesta. It is possible that females obtain nutrients from this behaviour while exerting some control over egg fertilization.     

The scramble competition mating system of the sphecid wasp Palmodes praestans (Kohl)

Males of the wasp Palmodes praestans engage in non‐territorial patrolling behaviour within a scramble competition mating system, showing great fidelity to their wide‐ranging patrolling routes without attempting to monopolize the areas covered. Scramble competition appears adaptive given that mating opportunities are not spatially aggregated in this species, whose females build isolated, single‐celled nests. Because of the female distribution pattern, a male's reproductive success in P. praestans probably depends upon the ability to find highly scattered, unmated females. The females of some close relatives of this sphecid wasp form fairly dense nesting aggregations. As mating system theory predicts, the males of some (but not all) of these species focus their searching at these concentrated nesting/emergence sites where potential mates are clustered spatially.     

XL.—A new Fossil form of Phasmatodea from Galkino (Turkestan), and on Mesozoic Phasmids in general

Insects of many groups form mating aggregations on hilltops. Males of some hilltopping species behave like certain classic lekking vertebrates, notably in their defense of territories that are devoid of resources useful to females but which are visited by females solely for mating. But even within a sample of 11 hilltopping insects found in the same habitat in central Arizona, there is considerable diversity with respect to resources transferred to mates by males, the degree to which males are aggregated and territorial, and the extent to which females can choose freely among hilltopping males. Thus ‘hilltopping’ is not a single mating system type; although some species conform closely to the traditional definition of a lek, others are very different. The ecological basis for the diversity in the behaviour of male hilltopping insects appears linked to differences in population density, which affect the costs of territoriality, and differences in the nature of female choice, which are little understood as yet.     

Spawning behaviour and sexual dimorphism in the North American cyprinid fish Notropis leedsi,the bannerfin shiner

The spawning behaviour and sexual dimorphism of the little known North American cyprinid fish, Notropis leedsi, is described based on observations made in laboratory aquaria. Notropis leedsi is a crevice spawning species, a trait characteristic of members of the subgenus Cyprinella. Males establish breeding territories through ‘mock battles’ and defend them by chasing away intruding males or, at times, through threat displays or ‘mock battles’. Although wild-caught males are significantly larger than females, sexual dimorphism is more pronounced in the colour pattern and fin size, especially the dorsal and anal fins.

The modes of spawning behaviour in the genus Notropis are reviewed. The relationship between the promiscuous mating system (polybrachygamy), the crevice spawning mode, and sexual dimorphism in N. leedsi are discussed in relation to current notions regarding sexual selection.     

The Biology and Development of Brachygaster minutus Olivier (Hymenoptera: Evaniidae), a parasite of the oothecae of Ectobius spp. (Dictyoptera: Blattidae).

Summary

Brachygaster minutus is a parasite of the oothecae of three species of British field-dwelling cockroaches belonging to the genus Ectobius. This species has previously received very little attention probably due to its restricted occurrence in Britain and the difficulties encountered in its collection. The life cycle and development of the parasite is described. The species is solitary in habit, the single larva overwintering within the ootheca as a final instar. The emergence of the adult the following summer is perfectly synchronized with the occurrence in the field of the particular cockroach species. Aspects of the mating and oviposition behaviour of the parasite are described.     

The polymorphism of a lygaeid bug Oxycarenus (Oxycarenus) multiformis Samy

Summary

The new species Oxycarenus (Oxycarenus) multiformis Samy has been found to be a polymorphic species. Four colour forms have been found: red, banded, spotted and black. Breeding experiments under laboratory conditions have indicated that dominance is nearly complete in the order given and that the second generation is segregated in the 3:1 ratios.

These colour forms have been given the taxonomic status of a single species on the basis of: (a) identical measurements of external characters, (b) similar morphological characters in the male genitalia, (c) equal fertility of each form, (d) free interbreeding, (e) random mating, (f) occupation of the same geographical regions, and (g) host plant relationship.     

Prolonged parental behaviour by males of Limnonectes palavanensis (Boulenger 1894), a frog with possible sex-role reversal

ABSTRACT

In sex-role-reversed systems, males carry out all parental care duties, forgoing further mating opportunities. Cases of complete sex-role reversal have not been reported in anurans. We describe the parental care behaviour of the leaf-litter frog Limnonectes palavanensis, a Bornean endemic with egg-guarding and tadpole transport, possibly the first anuran with sex-role reversal. In this study, we tested one of the predictions of the sex-role reversal hypothesis: males invest more in parental care than females do, and this prevents them from quickly acquiring additional mates. We observed egg-guarding behaviour in captivity to determine the length and intensity of parental care. Also, we describe the tadpole climbing and tadpole transport behaviour. We found that males perform all of the parental duties, remaining with the clutch until hatching. They do not call during this time, nor do they care for more than one clutch at a time. Observations of tadpole transport in the field indicate that all tadpoles in the clutch are retrieved at once. The behaviour of males during tadpole retrieval suggests that they stimulate synchronous hatching. Together, these results indicate that the male parental expenditure in this species is high, resulting in lost mating opportunities. The prolonged male-only parental care behaviour of this species satisfies an important criterion for the occurrence of sex-role reversal.     

Mating behaviour in two closely related sympatric species of Philonthus (Coleoptera: Staphylinidae)

Summary

The intra-specific mating behaviour of two closely related sympatric staphylinid beetles, Philonthus cephalotes (Grav.) and P. sordidus (Grav.) is described in detail. Mating is essentially similar in the two species, although differing in the duration of copulation (1·7 min in cephalotes, 44·6 min in sordidus), and consists of four phases (A)-(D); (A) pre-copulatory phase, (1) examination of female abdominal apex by male, (2) examination of male abdominal apex by female, (3) prolonged examination of female by male, (4) mounting by male (5) extrusion of male genitalia; (B) copulatory phase; (C) terminal phase; and (D) post-copulatory phase.

An attempt to test the role of species specific patterns of peg setae, occurring on the genitalia of males, as a tactile signalling system was made by observation of inter-specific interactions between males and females of the two species. Under the trial conditions inter-specific intromission did not occur and behaviour was predominantly aggressive. Evidence suggests that signals during the early stages of an encounter between the sexes of different species are generally sufficient to deter further courtship. In two instances courtship reached a more advanced stage and here the patterns of peg setae on the male genitalia may have come into play, operating as a signalling device.     

Breeding behaviour and mating success of Phyllomedusa rohdei (Anura,Hylidae) in south‐eastern Brazil

Observations on the courtship behaviour, mating behaviour and mating success of a leaf‐frog, Phyllomedusa rohdei, population were conducted in a temporary flooded site of the Atlantic Forest, south‐eastern Brazil. We did not find any influence of size and body weight on male mating success across three scales: seasonal, nightly chorus and local groups (males found within 1?m of a mated pair). In addition, no evidence was found that female Phyllomedusa rohdei exhibit overt mate choice. The formation of mated pairs in P. rohdei occurred because males moved toward the females, rather than reverse. The only variable that was significantly related to male mating success was the number of nights of participation in chorus activity. Besides calling tactics, males showed active searching behaviour. There was no evidence of size‐ and mass‐assortative mating, and a high percentage of fertilization at all size and mass ratios of males and females was observed. Clutches in this species are produced in the same manner found in others members of Phyllomedusa; a purse‐like nest is made over water by folding a leaf around the egg mass (embryos and fluid‐filled capsules). Finally, we supply a list of several studies that examined the relationship between size or mass ratios of males and females in amplexus and its influence on fertilization rate, and show that size‐assortative mating in anurans is inconsistent (present in some species but not in other).     

Asymmetrical male mandibular horns and mating behavior in Agathidium Panzer (Coleoptera: Leiodidae)

Males of some species of Agathidium Panzer have a prominent horn on the dorsal surface of the left mandible. The horn is unique in that it is highly asymmetrical. One species, A. marae Miller and Wheeler, has an additional horn on the right side of the frons. The horns are categorized into four general morphological types. Scaling relationships are investigated for two species, A. angulare Mannerheim and A. pulchrum LeConte. These species exhibit a scaling relationship that is strongly discontinuous (sigmoid) with a prominent “switch point”. Measurement data (pronotal width versus mandible height) are fit to a nonlinear regression model to determine the switch points and slopes at the switch points for the populations of each species. Behaviors associated with mating and other behaviors are described for A. pulchrum. Males use a head‐thrusting behavior to dislodge rival males from the substrate. Horned males appear better able to dislodge opponents. Head thrusting is also used less vigorously on females before and after mating.     

A study of the anatomy of Pupa and Maxacteon (Acteonidae,Opisthobranchia), with an account of the breeding cycle of Pupa kirki

Summary

The external features, mantle cavity, reproductive system and nervous system of Pupa kirki (Hutton, 1873) and three species of Maxacteon Rudman, 1971 are described and compared with Acteon tornatilis (L). It is suggested that the reproductive system of Pupa and Maxacteon, with two accessory sacs, the gametolytic sac and an exogenous sperm sac, is more primitive than that of Acteon tornatilis.

The breeding cycle of Pupa kirki shows that the species has a basic annual cycle, a few specimens surviving for two years.     

A comparative study of the mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri (Anura: Ranidae) from syntopic and allotopic populations

The mating call of Pelophylax ridibundus and Pelophylax kurtmuelleri from three syntopic and five allotopic populations was studied. All recordings were made during the mating season. We tested the hypothesis that the call of P. ridibundus from allotopic populations would differ from that in syntopic populations with P. kurtmuelleri. For the comparative analysis we used univariate and multivariate statistical methods and the following characteristics: call duration, pulse group duration, pulse group interval, pulse group period, pulse group number, minimum, maximum, fundamental and dominant frequencies and pulse energy. Analyses reveal a trait divergence in most of the studied characteristics of the signals, with stronger differentiation between P. kurtmuelleri and P. ridibundus in syntopic populations than between the two species in allotopic ones. The possible evolutionary implications of this divergence are discussed.     

Comparison of natural histories and karyotypes of two closely related ant‐eating spiders,Zodarion hamatum and Z. italicum (Araneae,Zodariidae)

Based on morphological characters, two species of the genus Zodarion, Z. hamatum and Z. italicum, were placed into the italicum group. The aim of this study was to evaluate similarity of these two species in respect of various aspects of their natural history and karyotypes. Both species had similar phenological patterns, being univoltine, but some specimens reached adulthood the same year before winter. Both representatives had nocturnal activity and were able to capture various ant species. Zodarion hamatum seems to be specialized on Myrmicinae ants, and Z. italicum on Formicinae ants. Zodarion hamatum showed more agile predatory behaviour than Z. italicum presumably due to specialization on Myrmicinae ants, which have lower population density. Both species are generalized mimics of bicoloured (orange‐dark brown) ants, such as Lasius emarginatus; they performed similar courtship and mating. The two study species exhibited contrasting reproductive strategies. Zodarion hamatum spiders had higher fecundity than Z. italicum as a result of larger body size but Z. italicum had larger eggs than Z. hamatum. This is presumably an adaptation to different availability of prey ants. Both species had the same diploid chromosome number, sex chromosome system and pattern of X chromosome heteropycnosis in testes. Results support a very close relationship between these two Zodarion species.     

New species of Orasema (Hymenoptera: Eucharitidae) from Central and South America

ABSTRACT

Six new species of Orasema are described. Four species are placed into a newly recognised lasallei species group: Orasema lasallei sp. nov. (Costa Rica, Honduras, Mexico, Nicaragua), O. janzeni sp. nov. (Costa Rica), O. peckorum sp. nov. (Brazil) and O. vasquezi sp. nov. (Colombia). One species is placed in the wayqecha group, Orasema masneri sp. nov. (Ecuador). One other species is currently unplaced to species group, O. longinoi sp. nov. (Costa Rica). Orasema lasallei was taken from a nest of Pheidole vorax (Fabr.) and an undescribed species near O. longinoi from a nest of Pheidole dossena Wilson (Myrmicinae). The morphology of the digitate labrum is discussed with respect to other Eucharitidae.     

Mating behaviour in the bees,Dieunomia heteropoda and Nomia tetrazonata,with a review of courtship in Nomiinae (Hymenoptera: Halictidae)

Males of many bees in the subfamily Nomiinae (Halictidae) have numerous secondary sexual characters, which provide much systematic information. Similarly, the use of these structures by males during sexual behaviour may provide useful characters, but the courtship and copulatory behaviour of most of these bees is not known. Structures and behaviour used for courtship and mating are described for two species of nomiine bees, Dieunomia heteropoda and Nomia tetrazonata, along with brief observations of mating in a parasitic bee, Triepeolus verbesinae (Apidae: Nomadinae). A review of mating behaviour within the Nomiinae shows no obvious phyletic patterns, based upon present limited knowledge. The species-specific nature of the male secondary sexual characters suggests they may have evolved in the context of sexual selection, but behavioural data from populations of additional species are needed to evaluate the hypothesis adequately.     

A revision of the Fabriciin genus Augeneriella Banse, 1957 (Polychaeta: Sabellidae)

The Sabellidae polychaete genus Augeneriella Banse is revised based on a reexamination of the type material of most species. Augeneriella hummelincki hummelincki Banse is shown to have vascularized, ventral filamentous appendages which can display up to four branches in a pectinate arrangement, as opposed to only a single dichotomy as originally described. The status of A. hummelincki indica Banse is discussed. The species A. bansei Hartmann-Schröder is based on a single, probably aberrant, specimen in which ventral filamentous appendages are unbranched. Additional material will likely show that this species displays the typical branched condition for ventral filaments. Augeneriella dubia Hartmann-Schröder can be ascribed to an undescribed genus which has been found in Atlantic, Indian, and Pacific Oceans. Two new species of Augeneriella from the Aldabra Atoll, Indian Ocean, are described.     

Food habits of the threatened bat Leptonycteris nivalis (Chiroptera: Phyllostomidae) in a mating roost in Mexico

The objective of this study was to collect and present data on the food plants that a vulnerable migratory nectarivorous bat, Leptonycteris nivalis, used during its seasonal stay at a cave in Tepoztlan, Mexico. This cave is the only mating roost known for this species. Pollen grains from faeces and fur were examined. Little is known about the diet of this bat, especially in the southern half of its distribution. Pollen belonging to 10 plant species was found from five families: Cactaceae (Stenocereus beneckei), Bombacaceae (Ceiba aesculifolia, Pseudobombax ellipticum), Convolvulaceae (Ipomoea arborescens), Fabaceae (Calliandra houstoniana, Bauhinia ungulata), and Amaryllidaceae (Agave dasylirioides, A. horrida, A. inaequidens, A. salmiana). Bats showed the highest dietary diversity in November. There were no significant differences in diet between sexes. Of the four Agave species, two have paniculate inflorescences that are commonly attributed to bat pollination, while the other two had spicate inflorescences, which are considered to be primarily insect‐pollinated.