Copulation Time Research Articles

Can male white-faced saki monkeys (Pithecia pithecia) detect female reproductive state?

Abstract For mammalian males, copulating with females during ovulation is critical to reproductive success. However male knowledge of ovulation may not always be advantageous for females, as it could hinder mate choice or promote harassment. White-faced saki monkeys live in variably monogamous and polygamous social groups and hence females may have multiple motivations to conceal ovulatory timing. White-faced sakis further show no obvious physical or behavioral signs of ovulation, although they do use scent in a variety of contexts, including sexual behavior. We collected data on three wild groups of white-faced sakis at Brownsberg Naturepark, Suriname in order to assess whether male copulations are coordinated with female ovulatory timing. We recorded all occurrences of copulations and genital inspections, and collected fecal samples from females which were radioimmunoassayed to obtain estradiol and progesterone levels. We found that males copulated throughout the female reproductive cycle, although the association between copulation and reproductive state varied between dyads. Only one male–female dyad showed significantly more copulations than expected during ovulation. However four of five dyads copulated less than expected with pregnant females, suggesting that males may be able to differentiate cycling from non-cycling females. While genital inspections were distributed randomly with regard to female reproductive state, the decision to copulate was not: males were more likely to mate with both ovulating and cycling females than with non-cycling females after genital inspection. Regardless, males were not more likely to copulate with an ovulating vs. a cycling (non-ovulating) female. These data indicate that while males may receive olfactory information on female hormonal status, they do not make entirely accurate decisions with regard to copulation timing. This inaccuracy may be due to males' inability to detect ovulation, or alternately a lack of motivation to limit copulations solely to conceptive periods. Pair familiarity and sexual experience may also play a role in copulation accuracy.

Mating and Sperm Storage of the Asian Shore CrabHemigrapsus sanguineus

The Asian shore crab Hemigrapsus sanguineus is the principal invasive crab in many intcrtidal habitats on the east coast of the United States between Cape Hatteras and Maine. Previous work has described general aspects of mating for the genus Hemigrapsus; however, there has been no explicit study of mating behavior in H. sanguineus, and there has been little consideration of how this behavior might influence the success of H. sanguineus as a bio-invader. The objective of our investigation was to document the mating behavior of H. sanguineus under laboratory conditions and compare this pattern of behavior with that of other species of Hemigrapsus. Our observations show that mating in H. sanguineus was always initiated by the male and that both the male and female had calcified exoskeletons at the time of copulation. Small males were sometimes successful in securing mates, even in the presence of larger males. However, the male was larger than the female in 67% of the observed copulations. Duration of copulation in H. sanguineus was relatively long compared with other species of Hemigrapsus, and averaged ∼30 min. H. sanguineus differs from other species of Hemigrapsus in terms of positioning during mating. H. sanguineus typically used a vertical position relative to the substratum, with both crabs standing and facing each other, ventral surface to ventral surface. This position facilitated some degree of mobility in the copulating pair. Females were receptive to copulation within a few days of larval release, and were also capable of storing sperm and producing at least 2 broods from a single copulation. Mean incubation time of newly extruded eggs was around 16 days, and females often produced a second brood within a few days of larval release. Thus, an individual H. sanguineus could produce 2 broods within 40 days and presumably additional broods with subsequent copulation. This pattern of reproduction provides enhanced fecundity relative to co-occurring native species of crabs.

First Report of Scent Collection by Male Orchid Bees (Hymenoptera: Apidae: Euglossini) from Terrestrial Mushrooms

Orchid bees (Apidae: Euglossini) are important pollinators of several angiosperms in the Neotropics, especially orchids (Dodson and Frymire, 1961; Dressler, 1968; Ramirez et al., 2002). Orchid bee males visit flowers that offer fragrances as resources to them as pollinators. This association is known as the ‘‘Perfume Flower Pollination Syndrome’’ (Vogel, 1963; Dressler, 1982). To collect fragrances, the males use their forelegs to adsorb scents that are subsequently stored in special structures located in their hindlegs (Dressler, 1982). Over the course of their lives, male orchid bees visit several plant species to collect floral sources, yielding a mixture of species-specific fragrances that has been shown to be correlated with a male’s age (Eltz et al., 2003; Zimmermann et al., 2006, 2009). These fragrances are used as part of the males’ displays at mating sites to attract females (Kimsey, 1980; Stern, 1991; Eltz et al., 2005a, b; Zimmermann et al., 2006) and it has been proposed that the fragrance mixture displayed by males could indicate mate quality to females (Kimsey, 1980; Eltz et al., 2003; Roubik and Hanson, 2004; Eltz et al., 2005a). However, this hypothesis has been difficult to test due to the short copulation time (,10 sec) and scarcity of observations describing the mating behavior in orchid bees (Stern, 1991; Eltz et al., 2003; Zimmermann et al., 2006, 2009). Although perfume flowers depend on orchid bees for reproduction, several studies have shown that this dependency is not reciprocal (Ackerman, 1983; Whitten et al., 1993; Pemberton and Wheeler, 2006; Cappellari et al., 2009). In addition to perfume flowers, orchid bees are known to collect scents from nonfloral sources like the surface of rotting wood, fruits and seeds, leaf litter, insecticides, and fragrant leaves (Roberts et al., 1982; Ackerman, 1983; Whitten et al., 1989, 1993; Ramirez et al., 2002). Here, we report the first field observations on volatile collection by males of Eufriesea violacea Blanchard on mushrooms growing in the ecotone between the Atlantic rainforest and the higher elevation Araucaria forest (600–1000 m ASL) of southern Brazil. The observations were conducted at the Forest Reserve Pro-Mata (FRPM), Sao Francisco de Paula, Rio Grande do Sul, Brazil (29u309050S, 50u109000W). This 5,000 ha area is characterized by patches of Araucaria trees, deciduous forest, shrub vegetation, and grasslands (Bertoletti and Teixeira, 1997). FRPM is located at the edge of the Araucaria plateau at a higher slope of the Atlantic rainforest remnants, and approximately 50 km from the eastern coast of Rio Grande do Sul. This area is considered the southern distribution limit of orchid bees in the Neotropical region (Wittmann et al., 1988). Bee vouchers were deposited at the LPB collection of the PUCRS Museu de Ciencias e Tecnologia in Porto Alegre, Brazil. Observations were made on the 27th of December, 2001, between 16:00 and 17:00. Six males of E. violacea were observed to collect volatiles from a fruiting body of a basidiomycete mushroom in a patch of forest (Fig. 1A). The males landed on the mushroom and scratched the lamellar gills with their forelegs. Short flights were undertaken after scratching the gills to transfer substances to their hind legs. Males displaced each other for a position close to the gills. The gills were entirely damaged at the time when we collected the mushroom which impaired its proper identification. Volatile collection at another mushroom was subsequently observed on January 5th, 2003, in an area close to the first observation site, when a single male was seen to scrape a fruiting body of a basidiomycete mushroom. The bee’s behavior followed the same pattern as previously observed: first the male scraped the fruiting body with its forelegs, and then hovered over the fruiting body to transfer collected substances to the hind legs. Based on the photographs

Seasonal Aplication of Jenter's Method for a Successful Queen Bees' Rearing in Albania

ABSTRACTThis research tested the rearing method of Queen Bees according to Jenter's. Two consecutive planting were realized, respectively on June 24 and July 12, each of these time-periods representing one stage of the experiment.To implement this research, the strongest bee-colonies of the apiary were used. During each stage of experiment 10 Queen Bees were produced. Their quality was judged and decided based on their growth parameters and performance.During each stage, the percentage of larvae's sealing, young Queen-Bees emergence, their time of copulation, their body size, the number of laid eggs were surveyed and measured. At the end of the research, it was concluded that Queen-Bees rearing parameters were better on the first stage of the study, all this due to the sufficient food availability and favourable climate conditions during this period of time. No significant differences were observed for the copulation time between two stages. During the second stage, the egg production is 27.7% lower than the first stage. The differences in value for the number of laid eggs in each stage are significant. The biggest size of the body-length and the maximum body weight of the Queen—Bees were reached during the June-July period (respectively 271.5 mg and 2.01mm).However, these parameters have been within the limits during the period of study.

Fellatio by fruit bats prolongs copulation time.

Oral sex is widely used in human foreplay, but rarely documented in other animals. Fellatio has been recorded in bonobos Pan paniscus, but even then functions largely as play behaviour among juvenile males. The short-nosed fruit bat Cynopterus sphinx exhibits resource defence polygyny and one sexually active male often roosts with groups of females in tents made from leaves. Female bats often lick their mate's penis during dorsoventral copulation. The female lowers her head to lick the shaft or the base of the male's penis but does not lick the glans penis which has already penetrated the vagina. Males never withdrew their penis when it was licked by the mating partner. A positive relationship exists between the length of time that the female licked the male's penis during copulation and the duration of copulation. Furthermore, mating pairs spent significantly more time in copulation if the female licked her mate's penis than if fellatio was absent. Males also show postcopulatory genital grooming after intromission. At present, we do not know why genital licking occurs, and we present four non-mutually exclusive hypotheses that may explain the function of fellatio in C. sphinx.

Female reproductive strategies in orangutans, evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion.

Intersexual conflicts over mating can engender antagonistic coevolution of strategies, such as coercion by males and selective resistance by females. Orangutans are exceptional among mammals for their high levels of forced copulation. This has typically been viewed as an alternative mating tactic used by the competitively disadvantaged unflanged male morph, with little understanding of how female strategies may have shaped and responded to this behaviour. Here, we show that male morph is not by itself a good predictor of mating dynamics in wild Bornean orangutans but that female conception risk mediated the occurrence and quality of male-female interactions. Near ovulation, females mated cooperatively only with prime flanged males who they encountered at higher rates. When conception risk was low, willingness to associate and mate with non-prime males increased. Our results support the hypothesis that, together with concealed ovulation, facultative association is a mechanism of female choice in a species in which females can rarely avoid coercive mating attempts. Female resistance, which reduced copulation time, may provide an additional mechanism for mate selection. However, coercive factors were also important as prime males were frequently aggressive to females and females used mating strategies consistent with infanticide avoidance.

A Technique for Distinguishing Virgin and Mated Males of Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae)

Studies on the mating history of male Lepidoptera are generally lacking because of difficulties in determining male mating status. In previous studies, presence/absence of pigmented fluids inside the male primary simplex have been used successfully for determining mating status. However, males of European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), have creamy white fluids in the primary simplex instead of pigmented fluids, so presence/absence of pigmented fluids inside the primary simplex cannot be used to assess mating status in this species. We developed a scoring system for the fluids inside the primary simplex that allowed us to classify O. nubilalis male mating status and the timing of copulation. The scoring system relies on differences in the fluids in the 1st, 2nd and 7th segments of the primary simplex. Males known to be virgins, mated <1d previously and mated >1d previously could be distinguished with a 6.3% error rate. The method was verified on 41 males in a blind study, with 100% accurate classification of the males.

Time‐shifted reproductive behaviours among fall armyworm (Noctuidae: Spodoptera frugiperda) host strains: evidence for differing modes of inheritance

The noctuid moth Spodoptera frugiperda consists of two strains associated with different larval host plants (most notably corn and rice). These strains exhibit differential temporal patterns of female calling and copulation during scotophase, with the corn strain more active earlier in the night. We investigated strain-specific constraints in reproductive timing, mating interactions between the two strains, and the mode of inheritance of timing of female calling, male calling, copulation and oviposition. We observed an allochronic shift of all reproductive behaviours by approximately 3 h and a parallel shift of nonreproductive locomotor activity, suggesting involvement of the circadian clock. The corn strain was more variable in the timing of calling and copulation than the rice strain. Rice strain females were more restricted in the timing of copulation than rice strain males, while such differences between the sexes were not apparent in the corn strain. There were significant interactions between the strains affecting onset times of copulation and male calling. The four investigated reproductive traits differed in their modes of inheritance: timing of female and male calling exhibited strong maternal effects, timing of copulation was controlled by a combination of maternal effects and corn strain dominant autosomal factors, and timing of oviposition was inherited in a corn strain dominant fashion. We conclude that the allochronic separation of reproduction between fall armyworm strains is asymmetric, less pronounced than previously thought, and under complex genetic control.

Copulation duration of bumblebee Bombus terrestris (Hymenoptera: Apidae): Impacts on polyandry and colony parameters

The influence of copulation duration on mating frequency and colony development were studied in Bombus terrestris (Hymenoptera: Apidae). Copulation time was recorded in transparent plastic boxes and was manipulated by separating mating pairs. Mean copulation duration was found to be 30.0 ± 8.0 (mean ± se) minutes and most matings lasted 20 to 40 min. When queens were only allowed to mate for 2 to 5 min, the chance that they would accept a second mating was 7.2 ± 5.0 % (mean ± se). Incompletely mated queens delayed to initiate colonies but they did not show significant difference from fully mated queens in production of new queens and males. This study shows that colony development was not affected by short copulation duration.

Sexual coercion in Panorpa scorpionflies?—The function of the notal organ reconsidered

Conflict between the sexes over the occurrence and timing of copulation is a common feature of sexual reproduction. In Panorpa scorpionflies (Mecoptera, Panorpidae), sexual conflict occurs over mating duration, and it has been suggested that the notal organ—a clamp-like structure on the males’ abdomen—is an adaptation to coerce mating duration, enabling males to prolong mating against female interests. However, as recent studies suggest that female scorpionflies have considerable control over mating decisions, we question this hypothesis and reexamined the function of the notal organ with respect to prolonged mating. We manipulated the notal organs of male Panorpa vulgaris and compared copulation durations achieved by males with functional and nonfunctional notal organs. There were no effects on the overall copulation duration or the period of time a copulation continues after the last nuptial gift has been delivered. We therefore reject the hypothesis that the notal organ is a male adaptation to extend copulation duration against female interests. Key words: copulation duration, Panorpa vulgaris, prolonged mating, sexual conflict, sexual selection. [Behav Ecol]

Pre‐copulation intervals, copulation frequencies, and initial progeny sex ratios in two biotypes of whitefly, Bemisia tabaci

AbstractThe whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.

MALE DISCRIMINATION OF FEMALE MUCOUS TRAILS PERMITS ASSORTATIVE MATING IN A MARINE SNAIL SPECIES

Recent research has shown the potential for nonallopatric speciation, but we lack an adequate understanding of the mechanisms of prezygotic barriers and how these evolve in the presence of gene flow. The marine snail Littorina saxatilis has distinct ecotypes in different shore microhabitats. Ecotypes hybridize in contact zones, but gene flow is impeded by assortative mating. Earlier studies have shown that males and females of the same ecotype copulate for longer than mates of different ecotype. Here we report a new mechanism that further contributes to reproductive isolation between ecotypes in the presence of gene flow. This mechanism is linked to the ability of males to track potential partners by following their mucous trail. We show that cliff ecotype males follow the trails of females of the same ecotype for longer than females of the alternate (boulder) ecotype. In addition, cliff males are more likely to follow the mucous trail in the correct direction if the trail is laid by a cliff-female. The capacity to discriminate the ecotype of female mucous trails combined with differential copulation times creates a strong prezygotic reproductive barrier between ecotypes of L. saxatilis that reduces gene flow from cliff to boulder ecotypes by >/=80%.

Male Mating Interest Varies with Female Fecundity in Pan troglodytes schweinfurthii of Kanyawara, Kibale National Park

Female chimpanzees mate promiscuously during a period of extended receptivity marked by prominent sexual swelling. Recent studies of wild chimpanzees indicate that subtle variations in swelling size could act as a reliable cue of female fertilization potential both within and between cycles (Emery and Whitten Behavioral Ecology and Sociobiology, 54, 340–351, 2003; Deschner et al. Hormones and Behavior, 46, 204–215, 2004). Copulation rates increase during the periovulatory period and during conception cycles (Deschner et al. Hormones and Behavior, 46, 204–215, 2004; Emery Thompson American Journal of Primatology, 67, 137–158, 2005a), suggesting that males may be able to assess female fertilization potential. We asked whether facultative timing of copulation in Kanyawara chimpanzees was due to increased male mating interest or to increased female proceptivity during the most fecund days. We assessed multiple measures of male mating effort in cycles aligned relative to the day of detumescence and compared periovulatory days to other days of maximal swelling, and conception cycles to nonconception cycles. The rate and proportion of male initiative in soliciting sexual behavior increased during periods of highest fertilization potential. Males were also more likely to interrupt copulations, associate with estrous females, and compete with other males when females were most likely to conceive. Females initiated copulations more frequently during conception cycles but did not visibly shift mating behavior within cycles. Our results support the hypothesis that male chimpanzees have the ability to assess the profitability of mating attempts, a trait that may act as a counter-adaptation to female strategies to obscure paternity. We discuss potential cues and the implications for female reproductive strategies.

Testosterone profiles and their correlation with sexual libido in male camels

The study was conducted on 4 male Jaisalmeri camels ( Camelus dromedarius) on their circulating testosterone (T) profiles and correlation with sexual libido. The average T concentration was low during hot months of April to September, started increasing in the months of October and November, continued to increase steadily in the months of December, January and February followed by decline in the ensuing months. Individual variations in onset and cessation of T surge were observed. Sexual libido as indicated by copulation time (CT) and volume of semen ejaculated (V) was high during January to April months, declined slowly over May month followed by complete cessation in later half of June. Sexual libido was almost negligible during July to November months. The sexual libido was also low during December month. Like circulating T profiles, individual variations were also observed in sexual libido. Data indicated that onset as well as cessation of T surge preceded the onset and cessation of sexual libido in all the animals. A positive correlation was found among circulating T (concentration), CT and V of semen. It is concluded that seasonal changes in circulating testosterone governs sexual libido in male camels.

Copulation behaviour of Neptunea arthritica: baseline considerations on broodstocks as the first step for seed production technology development

Copulation trials under three different scenarios were performed aiming to study the copulation behaviour of Neptunea arthritica and determine whether broodstock maintenance is required for artificial seed production. Neptunea arthritica showed polygamy, copulating at least three times with different partners. From all males and females used in this study, 43% of them copulated at least once. Female whelks showed rejection behaviour, which generated significant difference in copulation time between rejected (13.7±10.7 min) and non-rejected (49.7±44.7 min) males. The effect of body size on copula duration appeared to be superficial, while its effect on accumulative copulas played an important role as an indicator of copulation capacity because whelks varied in size. After first copula, males showed a contrasting tendency to mate copulated females over non-copulated females (χ2=6.23, d.f.=1, P=0.01). Broodstock maintenance as the first step in seed production is possible but considering low mating percentage and female rejection, it would be not economically reasonable due to the considerable number of whelks required and related logistical factors.

Reproductive Asynchrony and the Divergence of Hawaiian Crickets

AbstractAsynchrony in reproductive behavior may contribute to reproductive isolation among sympatric species. While the 38 cryptic species of the genus Laupala are primarily distinguished on the basis of variation in pulse rate of male calling songs, additional phenotypes, such as asynchrony in reproductive behavior, may contribute to reproductive isolation in this genus. Here we document similarities and differences in the diel timing of two reproductive behaviors, male singing activity and insemination events. Asynchrony in the diel timing of male singing behavior was observed between two sympatric species, Laupala cerasina and Laupala paranigra, in the field. An interpopulational comparison within L. cerasina did not reveal variation in diel behavior patterns of singing between two locations. Asynchrony in the timing of copulation and sperm transfer between L. cerasina and L. paranigra was documented in the laboratory. The observed pattern of asynchrony in both the field and laboratory could have arisen in a number of ways. One possibility is that species diverged in sympatry because of interspecific interactions, producing a pattern of reproductive character displacement. Alternatively, the observed asynchrony in reproductive behavior may have played a role in the process of community assembly within this recently diverged cricket genus. The presence of interspecific variation and the absence of intraspecific variation revealed by our study do not support a pattern of reproductive character displacement for diel reproductive behavior, suggesting that the differences seen between species were not caused by recent species interactions.

Sexual conflict over copula timing: a mathematical model and a test in the yellow dung fly

Sexual conflict over mating occurrence, timing, or duration is common in animals. This explains conspicuous female mate rejection behavior in many species, often involving shaking, fighting, and occasional forced copulations. We present a simple model that generates predictions about whether and when copulation occurs in such conflict situations and how much female rejection behavior should be observed. Predictions depend on 2 underlying parameters affecting female resistance and male persistence. We supply 2 qualitative tests of the model using the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae). We manipulated adult age, body size (large and small), and adult food availability (low and high), independently in males and females, staging replicate pairings of all treatment combinations. In agreement with predictions of our model, shaking duration first increased to a maximum at intermediate age, when the average female copulated, and then decreased again. Contrary to expectation, body size did not affect copulation timing, female resistance, or male persistence. As predicted, adult food limitation delayed sexual maturity and hence prolonged female resistance, resulting in later copulations after more shaking. However, although food limitation equally delayed the increase in male persistence with age, copulation also occurred later after more shaking, opposite to the model prediction. We conclude that shaking is driven primarily by female age and male responses to it. Although female shaking can initially successfully deter males in S. stercoraria, this behavior is subtle and has apparently shifted function from an effective means of mate choice to a signal of nonreceptivity, though its importance in nature remains unclear. Key words: body size, copulation duration, food limitation, Scathophaga stercoraria, Scatophaga, sexual conflict, sexual selection. [Behav Ecol]

Timing of copulations and the pattern of paternity in relation to laying order in tree swallows Tachycineta bicolor

It is well established that extra‐pair young are present to varying degrees in nests of most avian species. However, the timing of extra‐pair copulations during a female's fertile cycle is not well known, nor is how these copulations translate into the distribution of extra‐pair young within the laying sequence. We determined the rates of successful within‐pair copulations where at least one cloacal contact was achieved, and the number of extra‐pair copulations/attempts in 17 pairs of tree swallows Tachycineta bicolor during the mornings encompassing the female's fertile period. We also examined nestling paternity with respect to laying order in eighteen mixed‐paternity tree swallow broods. The rate of successful within‐pair copulations peaked three days prior to a female laying her first egg, and decreased steadily throughout the laying period. We therefore predicted that extra‐pair young would be more likely to hatch out of later‐laid than earlier‐laid eggs within a female's brood. We found no evidence of an increased frequency of extra‐pair young with laying order. Instead, extra‐pair young appear to be randomly distributed within the laying sequence of tree swallows.

Density-dependent effect on reproductive behaviour of Lysmata amboinensis and L. boggessi (Decapoda: Caridea: Hippolytidae)

We compared the reproductive behaviours of two protandric simultaneous hermaphroditic species (Lysmata amboinensis and L. boggessi) that belong to two groups of Lysmata shrimp with different morphology, geographical distribution, and density. Lysmata amboinensis occurs in tropical waters at low population densities, and L. boggessi is found in aggregation in sub-tropical and temperate areas. Reproductive behaviour of L. boggessi under two densities and L. amboinensis in different habitats were compared. Results show that L. amboinensis was much less active during mating than L. boggessi. Male shrimp of L. amboinensis did not display obvious pre-copulation behaviour. They also took significantly longer to transfer spermatophores and lay eggs after mating than L. boggessi shrimp did. For L. boggessi, moulting time of female shrimp, copulation time and the interval between moulting and mating were significantly shorter when three male shrimp were present than when only one male shrimp was present. Our study suggests that the reproductive behavioural differences in the two shrimp species are possibly the results of density-dependent effect.

Mating Behavior and Species Status of Host-Associated Populations of the Polyphagous Thrips, Frankliniella schultzei

The thrips taxon, Frankliniella schultzei Trybom, could possibly comprise a complex of unrecognised cryptic species. We therefore made a range of reproductive behavioral observations on F. schultzei individuals from different host-associated populations to investigate their species status. We first described the mating behavior of F. schultzei taken from flowers of a primary host species, Malvaviscus arboreus. The pattern of male-female interaction was complex and protracted, with several behavioral steps being performed. These steps were similar for all mating pairs. Most females responded to male presence before physical contact, suggesting that male pheromones may be involved. We then compared mating behaviors, brood sizes and sex ratios of F. schultzei pairs derived from different host plant species. All pairs in crosses regardless of their original host plant species produced female offspring, indicating successful mating. Frequencies of behaviors were similar for all pairs. Only those crosses involving F. schultzei individuals from Erythrina crista-galli flowers differed from the general pattern in pre-copulation and copulation times. The females from E. crista-galli also produced significantly fewer offspring than females from other crosses. Finally we used traps baited with males from two populations, but set among flowers of one host plant species, to test for differential attraction of females. We found no evidence that the different host-associated populations investigated differ from one another functionally in their sex pheromone system. However, these results do not yet discount the possibility of cryptic species within the taxon F. schultzei. Populations of F. schultzei on many other host species need to be investigated from this perspective.