Sexual dimorphism in chelicerae,forelegs and palpal traits in two burrowing wolf spiders (Araneae: Lycosidae) with sex-role reversal

Allocosa alticeps and Allocosa brasiliensis are two sex-role-reversed spiders. Females locate males and initiate courtship. Copulation occurs inside male burrows and after copulation the males deliver their burrows to the females. We explored the occurrence of differences in morphological traits related to sex roles in both Allocosa species and compared the results with two non-burrowing wolf spiders with typical sex roles. We measured the length of the foreleg's tibia-patella and the chelicerae. Scanning electron micrographs of palpal tarsus distal sections were taken. Males showed higher values than females in all the traits considered. Adult and penultimate males lacked true claws compared with juveniles and females, but showed modified spines. The palpal organ was more proximal to the tibia compared with the non-burrowing lycosids considered in this study. Spines and palpal organ location could be associated with more effective digging. We discuss how natural and sexual selection could interact on morphology in this scenario.     

Mating behaviour and spermatophore transfer in the shrimp Heptacarpus pictus (Stimpson) (Decapoda: Caridea: Hippolytidae)

Summary

Heptacarpus pictus, a small caridean shrimp inhabiting the low intertidal of southern and Baja California, breeds during the winter, spring, and summer months. Fall is a period of growth. Life span of an individual does not exceed 18 months, with fish predation as the most likely source of mortality.

Females are multiple brooders, carrying developing embryos concomitant with increase in ovary size. Hatching of larvae is followed by a moult, after which the female is attractive to males and receptive to copulation. A distance pheromone does not appear to be involved in attraction of males to females. Males apparently respond to a non-diffusible substance on the exoskeleton of newly moulted females.

Precopulatory behaviour is absent. Copulation can be divided into a series of relatively stereotyped events. Female rejection of the male or his spermatophore is the chief cause of unsuccessful matings.

Males deposit the spermatophore on the underside of the female's first abdominal segment. Sperm packets are formed upon extrusion from the male's genital openings, and are composed of a mucoid material in which sperm are mixed. The glutinous spermatophores adhere to the female's smooth abdominal sternite.

The endopods of pleopods 1 and 2 of the male are different in shape, size and setation from homologous rami of females and juveniles. Endopods of pleopod 1 possess a distally located appendix interna, absent in juveniles and females. An anteriorly projecting process, the appendix masculina, is located on the endopod of pleopod 2 in males. Experiments were performed which showed that these modifications insure proper deposition of spermatophores. Males which had the copulatory rami removed did not transfer spermatophores as successfully as normal males.

Transfer of the spermatophore from the male to the female is a result of the interplay of male pleopods 1 and 2 during copulation. The large expanded abdominal pleurae of females prevent the male's genital opening from contacting her abdominal sternite. Thus, the male's anterior pleopods have become modified to lift the emitted spermatophore from his genital orifices to the first abdominal sternite of the female.     

Copulatory courtship and morphology of genitalic coupling in seven Phyllophaga species (Coleoptera: Melolonthidae)

Males in six of seven species of Phyllophaga perform apparent courtship behaviour during copulation. As predicted by the hypothesis that such copulatory courtship is under sexual selection by female choice, behavioural details differ between species. The modified male abdominal sternites, which rub against the female's pygidium during copulation and whose morphology also differs between species, and the flattened, setose tarsi of males of one species probably function as contact courtship devices during copulatory courtship. Observations of events inside copulating beetles were made through the semi-transparent abdominal sternites of females and male genitalia in three species. They revealed cryptic genitalic thrusting behaviour of male genitalia within the female which occurred even when there was little or no external movement of the male genitalia. Dissections of pairs frozen in copula demonstrated that males transfer large quantities of material to females during copulation that is not physically related to sperm transfer. The type of material varied between species. In at least two species most of the transfer apparently occurred after sperm transfer. The possibility that some male genitalic structures function as holdfasts and/or stimulatory devices was suggested by their positions relative to female structures, and/or their movements within the female. Portions of male genitalia with strong bristles tended to lie against setose or more heavily sclerotized portions of the female reproductive duct. Some portions of female genitalia which vary between species seem ill-designed to exclude the genitalia of cross-specific males. The female reproductive tract is partially everted during copulation in one species.     

Characterisation of burrow architecture under natural conditions in the sand-dwelling wolf spider Allocosa brasiliensis

Allocosa brasiliensis (Petrunkevitch, 1910) is a wolf spider that constructs silk-lined burrows along the coastal sand dunes of Argentina, Brazil and Uruguay. This species shows a reversal in typical sex roles and sexual size dimorphism expected for spiders. Females are the smaller and mobile sex, which initiates courtship at the male burrow entrance. Mating occurs in the male burrow, and when it ends, the male leaves and the female stays inside. Females prefer to mate with those males showing longest burrows, so burrow dimensions would be under strong sexual selection pressures. Previous studies in the laboratory indicated that male burrows are longer than those of virgin females, which were described as simple silk capsules. Preliminary observations suggested that juvenile burrows presented differences from those of adults; however, detailed observations of A. brasilienisis burrow characteristics at the field were lacking. The aim of this study was to characterise the burrows of adults and juveniles of A. brasiliensis under natural conditions. We recorded the dimensions of burrows inhabited by males, females and juveniles (n = 30 for each category) and created beeswax moulds that reflected burrow shape. Juveniles inhabited tubular burrows with two branches and two openings; on the contrary, adults were found in tubular burrows with a single entry. Males and females inhabited burrows of similar length and width, but those of juveniles were shorter and narrower. We discuss the results and their possible functional explanations according to the selective pressures expected for each developmental stage and sex.     

Natural history and behaviour of the primitively eusocial wasp Ropalidia marginata (Hymenoptera: Vespidae): a comparison of the two sexes

We report the natural history and behaviour of the primitively eusocial wasp Ropalidia marginata with a special reference to the males. We found that just as nests of this species are found throughout the year, so are the males. Females spend all their life in their nests but males stay in their natal nests only for 1–12 days and leave to lead a nomadic life. Males maintained in the laboratory can live for up to 140 days. Like all eusocial hymenopteran males, R. marginata males also do not perform any colony maintenance activities. We found that males did not forage or feed larvae. Compared with females, males showed fewer dominance and subordinate behaviours and being solicited behaviour and more feeding self and soliciting behaviours. By comparing males with young females, we found similar differences, except that the males showed similar rates of feeding self and higher rates of subordinate behaviour.     

The function of the sphragis in Cressida cressida (Fab.) (Lepidoptera,Papilionidae): a visual deterrent to copulation attempts

During mating, males of Cressida cressida (Lepidoptera, Papilionidae) form a large external mating plug or sphragis that covers the female's copulatory opening and physically prevents remating. The sphragis has lateral and distal projections that make it an obvious structure. We tested experimentally the hypothesis that the sphragis acts as a signal of female mating status. Males pursue mated females with an intact sphragis only briefly and rarely make physical contact with them. When the sphragis of a mated female is removed or reduced in size, males are significantly more likely to physically contact the female and initiate the aerial takedown that preceeds a copulation attempt. These results suggest that the sphragis deters male sexual interest at a distance and thus functions as a signal of female mating status. The discussion focuses on the fitness consequences for females and their mates of the signal function of the sphragis.     

Mating behaviour,territoriality and natural history notes of Phyllomedusa ayeaye Lutz, 1966 (Hylidae: Phyllomedusinae) in south-eastern Brazil

The mating (male courtship, amplexus and oviposition) and male territorial behaviours of Phyllomedusa ayeaye are described from a high-altitude site in the state of Minas Gerais, south-eastern Brazil. Information related to male breeding success and territoriality, as well as egg clutch parameters, is provided, together with qualitative information regarding tadpole phenology and juvenile recruitment. In addition, estimations of sexual dimorphism and numbers of marked individuals are available through capture-mark-recapture sampling. Females bred with males within spatially clustered oviposition sites (broadleaf plants). In some cases, the amplectant couple actively searched for the oviposition site. Males defended territories from other males, employing both acoustic and physical interactions. Some males successfully maintained their calling sites over successive nights, and others seemed to switch among nearby sites during successive nights and tried to disrupt ongoing ovipositions. No significant relationship was found between physical attributes (snout vent length or body mass) of males with breeding success. Also, no influence of the number of nights a male was active in chorus and its breeding success was detected. Therefore, it is proposed that the mating system in P. ayeaye may be opportunistic. Additional information related to reproduction (egg clutch parameters and breeding behaviours) is also discussed for other species of the Phyllomedusa hypochondrialis group and compared with the results of the present study.     

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.     

Bauble spiders: a new species of Achaearanea (Araneae: Theridiidae) with ingenious spiral retreats

A new species of Achaearanea (Theridiidae) is described from the Cedarberg in South Africa. Its unusual morphological features include the position of the spinnerets directly behind the epigastric fold. The male palp is a modification of the palpal conformation of other Achaearanea. This spider lives in a spherical retreat comprizing silk, sand and pebbles. This structure typically dangles from only one thread and has a tiny opening at the bottom that leads into a spirally-coiled tunnel. Males and females build spirals in opposite directions. This enables the male to construct his retreat against that of the female in such a way as to form a brood chamber. Retreats are situated in cool places under low overhanging rocks or branches. The configuration of the narrow, suspended retreat may decrease the spider's vulnerability to enemies while foraging for ants in a typical theridiid fashion.     

Courtship,copulation and oviposition in the chalcedon checkerspot,Euphydryas chalcedona (Lepidoptera: Nymphalidae)

In this report we describe some aspects of the reproductive biology of a population of the chalcedon checkerspot, Euphydryas chalcedona, in central Arizona. Successful courtship in this species lasts about a minute and has a form similar to that of other nymphalids. During copulation the male forms a spermatophore within the female's bursa copulatrix that represents about 7% of the male's body weight. After copulation females may remate and older females may have mated as many as three times. The spermatophore deflates as time since deposition passes. Females oviposit every other day on average and lay their eggs in clusters. These data confirm previous brief reports of courtship structure and spermatophore size for E. chalcedona. Questions are raised about the control of receptivity in this species and the function of the mating plug.     

Mating behaviour and sexual selection in the African ball-rolling scarab Khepher platynotus (Bates) (Coleoptera: Scarabaeidae)

Mating behaviour of the ball-rolling dung beetle Kheper platynotus (Bates), adults of which are active in rainy seasons, was studied in southeastern Kenya. Male mating behaviour changed with the progression of the rainy season. In the early season when females made food balls, males attempted forced copulation with wandering and food-ball-making females on dung mounds. As the season progressed, females made brood balls, and males attempted to pair off with such females, as well as attempting forced copulation with wandering and food-ball-making females. A male who paired off with a brood-ball-making female cooperated with the female to make the ball. The male usually copulated after burying the ball (pre-copulatory mate guarding), but sometimes copulated during ball-making. In the latter case the male usually showed post-copulatory mate guarding until ball burial, but sometimes left soon after copulation. In the late season, when available females decreased because of maternal care in the underground nests, males started to make food balls to secure food resources for survival until the next rainy season. Male mate guarding involving ball-making, -rolling and -burying seemed to function to raise paternity confidence, but such assistance seemed to be less beneficial to females. Fights frequently occurred between guarding and intruding males on brood balls. Both residency and relative body sizes of fighters were important asymmetries influencing contest outcome. This seemed to result in not active but passive mate choice by brood-ball-making females.     

Long copulations and post-copulatory ‘escort’ behaviour in the locust leaf miner,Odontota dorsalis (Coleoptera: Chrysomelidae)

The adult behaviour of Odontota dorsalis on its host plant Robinia pseudo-acacia was studied by following marked individuals in nature. Copulations often lasted several hours, and were characteristically followed by long escort phases in which males remain mounted atop females. Pairing lasted as long as several days. Most pairs broke up around the time of day when most females were ovipositing. Females normally laid a small cluster of eggs once per day. Both sexes mated repeatedly, and females did not resist copulations.

Long pairings in O. dorsalis may have evolved because the encounter rate between the sexes is high and costs to the female low. It is suggested that escort behaviour will be found in many other species with similar ecology and in which males remain mounted on females while copulating.     

Age,body size and growth pattern of Argenteohyla siemersi pederseni (Anura: Hylidae) in northeastern Argentina

In this study we analysed the body size, age structure, age at maturity, longevity and growth pattern of Argenteohyla siemersi pederseni in north-eastern Argentina using skeletochronological methods. Body size was sexually dimorphic; females were significantly larger and heavier than males, regardless of age. As A. s. pederseni is an explosive breeder with only one reproductive episode per year, we assumed that each Line of Arrested Growth (LAG) observed was equivalent to one period of decreasing growth, LAGs reflecting a direct estimation of individual age. The minimum number of LAGs counted was two for males and three for females, but there was no sexual difference in longevity. The von Bertalanffy's growth coefficients (K) were higher in males than in females for both size and body mass. Females had a lower growth rate than males, took longer to reach the minimum maturation size, and were older and larger at reproduction.     

“Riding” behaviour by males of Conops quadrifasciata (Diptera: Conopidae): Do females set up “riders” as targets for takeovers by larger males?

Males of Conops quadrifasciata “claim” females in late morning and then spend the rest of the day exposed as “riders” to attacks by other males. Male riders can respond to an attack by performing an abdomen‐lift which denies the attacker access to the female's genitalia. Attacking males can tailor their behaviour to suit the prevailing conditions. If a rider is engaged in a “repeat” copulation (as he does at regular intervals), the attacker “waits” beside the rider. If the rider is not in genitalic contact with the female, the attacker tries to mate with her immediately. It is proposed that females deliberately expose their riders to takeovers in order to gain the fittest mate.     

Antennation and sexual performance of male digger wasps Sphex ingens Smith (Hymenoptera: Sphecidae)

Antennation can play several roles in hymenopteran copulation, mainly in wasps. The digger wasp Sphex ingens Smith has a very peculiar sexual behaviour, in which forced copulation is a striking element. However, communication through antennation during the pre-copulation and copulation phases and the relationship between the sexual performance of males and the final result of copulation require further clarification. The sexual behaviour of wild populations of S. ingens was filmed during the breeding season in a site between the beaches Meros and Aventureiro, Ilha Grande, southeastern Brazil. We assessed antennation behaviour, courtship duration, sexual performance, and genital clasping. Only successful males had the genital clasping assessed. Evidence found so far points out that the successful males showed better sexual performance – that is, they antennated more in a shorter courtship duration. Also, genital clasping in successful males did not depend on antennation, courtship duration, or sexual performance. Our results shed light on some aspects of the sexual behaviour of wasps, as they explain part of the sexual selection mechanisms adopted by the species.     

Taxonomic and biological observations on the tiger flatworm,Maritigrella crozieri (Hyman, 1939), new combination (Platyhelminthes,Polycladida, Euryleptidae) from Florida waters

The tiger flatworm, Maritigrella crozieri (Hyman, 1939) (Platyhelminthes, Polycladida, Cotylea) new combination, is redescribed from eastern Florida and the Florida Keys. This marine flatworm is one of the most common polyclads within warm temperate to tropical west Atlantic, yet it has been misidentified consistently as a pseudocerotid. Animals were kept alive in the laboratory for 3 weeks for biological observations. Findings indicated that these euryleptids employ hypodermic insemination, with multiple copulations occurring over several days. Sperm was transferred in sperm bundles bilaterally with little apparent damage to the epidermis of the copulating worms. Copulation sessions were variable and lasted an average of 15.4 min. In situ and laboratory observations indicated that M. crozieri fed exclusively on the mangrove ascidian Ecteinascidia turbinata Herdman, 1880, an individual consuming one prey zooid in an average of 17 min and an average of 19 zooids over 24h.     

Reproductive ecology and behaviour of a species of Adenomera (Anura,Leptodactylinae) with endotrophic tadpoles: Systematic implications

The species of the Leptodactylus fuscus group and those of the genus Adenomera lay their eggs in underground chambers. According to current systematic arrangement of these genera, this behaviour is convergent. Here we describe reproduction, courtship, tadpole morphology, calls, chamber structure, and populational phenology of an Adenomera species, and compare some of these features with those of other species of the genus and with species of Leptodactylus of the fuscus and pentadactylus groups. We tested the tadpoles of the Adenomera sp. and those of Leptodactylus labyrinthicus (pentadactylus group) for their foam‐making abilities. There was sexual dimorphism in size; males averaged 22.0?mm and females 24.3?mm in snout–vent length. Males called from late September to late February; calling often began about 2–3?h before sunset. Males called exclusively in open (non‐forest) areas. Egg clutches were found around male calling sites. Males excavated spherical chambers which had a direct entrance. During mating, the male led the female towards a previously excavated chamber. Territorial interactions (aggressive calls and fights) occurred when an intruder male approached a calling male. Late‐stage tadpoles and newly metamorphosed juveniles were found within underground chambers. Clutch size averaged 10.6; eggs averaged 3.7?mm in diameter and were cream coloured. Tadpoles had horny beaks, but no labial tooth; spiracle was present. All tested groups of tadpoles generated foam within 10?h. As we report for Adenomera sp., the males of Leptodactylus species of the fuscus group lead the female to a previously excavated chamber. Tadpole foam‐making behaviour was reported in Leptodactylus of the fuscus group and was previously unknown for any species of Adenomera or for Leptodactylus of the pentadactylus group. The way in which the tadpoles of Adenomera sp., Leptodactylus spp. (of the fuscus group) and L. labyrinthicus made foam was quite similar. The foam‐making behaviour of the studied tadpoles may act to avoid compaction of the tadpoles at the bottom of the basin or underground chamber, avoiding overcrowding and increasing respiratory and excretory efficiency. As presently recognized, the phylogenetic position of Adenomera suggests that reproductive major behavioural features are convergent with some Leptodactylus species. Alternatively, our data point to close phylogenetic relationships between Adenomera and Leptodactylus of the fuscus and pentadactylus groups, reinforcing the paraphyletic nature of the genus Leptodactylus.     

Spatial and temporal patterns of territorial mate locating behaviour in Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae)

Male Hypolimnas bolina (L.) (Lepidoptera: Nymphalidae) defend perch sites as a method of visually locating receptive females. In this study we charted the spatio-temporal activity of perching males in tropical Australia to investigate (a) the extent to which male activity is thermally constrained, and (b) the physical attributes of selected perching sites. Butterflies were surveyed along two 5-15m wide open corridors through dense vegetation, and this allowed the prediction that males should favour narrower corridor sections in order to maximize their visual search capability. This prediction was supported. Beyond corridor width, the distribution of favoured perches was not explained any further by patterns of shading, larval food plant distribution, or the presence of nectar resources. Males were active from 0800 to 1700 h, but the number of perching individuals varied throughout the day, and this pattern varied between the two transects. Most individuals perched along one transect in the morning (0900-1100 h), whereas activity along the other peaked around midday (1100-1300 h). This between-transect difference in male activity followed changes in shading between the transects, however this variable did not predict male distribution at the territory scale. Although ambient and black body temperatures were significantly related to population-level activity, these variables only predicted 15-55% of the variance in male counts in individual transects. This result, viewed in conjunction with the limited available information on female receptivity, suggests that the timing of mate location in H. bolina may be primarily influenced by the daily pattern of female availability.     

A new genus and species of Heteromysini (Crustacea‐Mysidacea) from the backwater of Kochi (Kerala,India)

Kochimysis pillaii, a new genus and species of Heteromysini collected from the backwater of Kochi, is described. The new genus is closely related to the genus Deltamysis but is distinguishable from the latter by the following characters: antennules of male have a small setiferous lobe; antennal scale is without distal suture; second segment of mandibular palp broad; endopodite segments of maxilla subequal in length; in male carpus and propodus of second thoracic endopod with notches on outer margin; outer pair of apical spines on telson longer than the inner pair.     

A remarkable,new Australian sawfly with brachypterous,nocturnal or crepuscular females (Hymenoptera: Symphyta: Pergidae)

A new species of sawfly, Clarissa tasbates, is described from high subalpine (860 m), grassy eucalypt woodland in western Tasmania. Females have abbreviated wings with reduced venation, are nocturnal or crepuscular, and occur on the ground or on grass tussocks. Males are macropterous and both nocturnal and diurnal. Presumed larvae are ground dwelling and feed on Ranunculus.