Starvation and the Mating Success of Wild Male Mediterranean Fruit Flies (Diptera: Tephritidae)

Recent evidence suggests that the nutritional state of male Mediterranean fruit flies, Ceratitis capitata (Wied.) (medfly), is an important influence on various components of their reproductive biology, including mating success. The objective of the present study was to examine experimentally the effect of temporary starvation on the mating success of wild male C. capitata. Males were maintained on protein–sugar or sugar-only diets, and for each diet we compared the mating success of continuously fed males versus males starved for 18 or 24 h immediately before testing. In trials conducted on field-caged, host trees, males starved for 24 h obtained only about half as many matings as fed males for both diets. However, when the starvation period was 18 h, starved males reared on the protein–sugar diet mated significantly less frequently than fed males, whereas starved males reared on sugar mated as often as fed males. Measurements of male pheromone calling and female attraction revealed that reduced mating success likely reflected the decreased signaling activity of starved males.     

Multiple Mating and Reproductive Success of Male and Female Apple Maggot Flies, Rhagoletis pomonella (Diptera: Tephritidae)

Mature male and female apple maggot flies mated frequently on a field-caged host tree during a 14-day study. Each sex averaged one mating per day (mean of 1.0 ± 0.1), but some females mated up to eight times per day and some males up to six times per day. Reproductive success was estimated based both on observed numbers of matings in the field cage and on previous work relating fecundity and fertility to female mating status. Male and female flies did not differ in mean or variance in reproductive success, indicating that this is a polygamous mating system consisting of both polygyny and polyandry. We discuss the significance of this with regard to the framework of insect mating control and frequency proposed by others. We also discuss behaviors (such as movements, agonistic encounters, occurrences on fruit, and ovipositions) that do and do not show correlations with mating success in apple maggot flies.     

Chromosome polymorphisms and natural selection inLeptysma argentina (Orthoptera): external phenotype affected by a centric fusion predicts adult survival

The relationship between fitness variation associated with a quantitative trait and a Mendelian factor affecting that trait was examined in a natural population of the South American grasshopperLeptysma argentina. Previous studies have shown that a centric fusion between chromosomes 3 and 6 (fusion 3/6) increases adult survival and body size in this grasshopper. Here we examined the possible relationships among fusion 3/6, a size-related trait (prothorax height) and adult survival in a natural population. The study was based on two generations, comparing samples taken at the beginning and at the end of the adult life span. All individuals were karyotyped and scored for prothorax height (PH). A nonparametric regression analysis revealed that adult survival monotonically increased with PH in both generations. Moreover, fusion 3/6 was found to have an additive effect on this trait. Within generations, fusion frequency increased with adult survival in males (but not significantly so), as expected if phenotypic selection on PH influences the fusion polymorphism. Using regression analyses, we show that the correlation between PH and adult survival is not a purely environmental correlation genetically independent from the fusion polymorphism. A simple model is proposed for testing similar hypotheses in studies of selection on a trait influenced by a known genetic polymorphism.     

Chromosome Inversion Polymorphisms Influence Morphological Traits in <Emphasis Type="Italic">Trimerotropis Pallidipennis</Emphasis> (Orthoptera)

Trimerotropis pallidipennis is a New World grasshopper whose South-American populations are polymorphic for six pericentric inversions. Previous work has demonstrated that the frequences of these inversions correlate with climatic variables, and hence a possible adaptive pattern was put forward. In the present work we analysed a sample of a natural population of T. pallidipennis to ascertain whether the chromosomal inversions have effects on exophenotypes. Two hundred and sixty-eight males coming from a natural population at Uspallata, Mendoza Province, Argentina were analysed, and it was observed that most inversions had significant effects on phenotypes. Furthermore, some body size-related characteristics (such as tegmina length) were correlated with the number of inversions. Individuals from populations at higher altitude or latitude (i.e., at lower minimum temperatures), along with higher frequencies of standard sequences, were significantly smaller, and this coherence between interpopulational with intrapopulational results may indicate that the diminished body size of the standard sequence-carrying individuals may be caused by an effect of the inversions, or genes within the inversions, on body size. We finally put forward the hypothesis that reduced body size in a context of reduced minimum temperature may be a response to shortened development season, and so smaller individuals may be advantageous.     

Virgin male mating advantage in a primitive acoustic insect (Orthoptera: Haglidae)

Male reproductive behavior in the relict flightless haglid, Cyphoderris strepitans,entails the generation of sound signals and the provision of nuptial gifts to mates. These food gifts take two forms: (1) a gelatinous mass (spermatophylax) augmenting the spermatophore and (2) fleshy metathoracic wings adapted to be eaten. The female consumes a portion of the male's underwings during courtship and copulation and the spermatophylax afterward. The incidence of wing-feeding wounds can be used to monitor the mating success of field-caught males. If, when a male mates, he compromises his ability to provide subsequent nutritive gifts, females would benefit by mating with virgin rather than nonvirgin males. To test this, mating success of virgin and nonvirgin males was compared in a field population. Virgins were found to obtain more matings than explained by their numbers relative to nonvirgins in the population. We conclude that, having mated, a male is at a disadvantage, relative to his virgin competitors, in securing further matings.     

Fluctuating Asymmetry and Male Mating Success in a Sphragis-Bearing Butterfly Luehdorfia japonica (Lepidoptera: Papilionidae)

The relationship between fluctuating asymmetry (FA) and mating success was studied within males of the sphragis-baring butterfly Luehdorfia japonica, which were collected at various periods during their mating season. FA was measured on the forewing and hindwing radius lengths of male butterflies. Mating frequency of males was estimated by assessing the degree of scale loss from their claspers. Males consume scales and use them to form sphragis on the female abdomen during copulation, sealing the ostium bursa for life. Age of males was scored as wing age 0 to 4 according to the wearing of the wing. FA was negatively correlated with mating frequency but positively correlated with wing age, and average FA decreased with mating season. As females have little chance to express mate choice, it is likely that FA is an indicator of male viability: symmetrical males live longer and/or fly more actively, resulting in a higher lifetime mating success compared to asymmetrical males.     

Male Dominance Rank,Female Mate Choice and Male Mating and Reproductive Success in Captive Chimpanzees

Mating and consequently reproductive success in male vertebrates are predominantly determined by intermale competition and female mate choice. Their relative importance however, is still poorly understood. We investigated the interrelationship between male dominance rank — a formal indicator of male competitive ability — female mate choice, and male mating success in a multimale-multifemale group of captive chimpanzees. In addition, we examined the relationship between male dominance rank and reproductive success determined by genetic paternity analysis over a 13-yr period in the same captive population. We related the frequencies of sociosexual behaviors to the female anogenital swelling stage and female fertile phase as determined by urinary and fecal progestogen analysis. Rates of behaviors in both sexes increased with increasing intensity of female swelling, but they were not influenced by the timing of the fertile phase. Male mating success was clearly related to male dominance rank, with high-ranking males performing the overwhelming majority of copulations. This was mainly due to both rank-related rates of male soliciting behavior and intermale aggressiveness during the period of well-developed female anogenital swelling. Although females solicited copulations mainly from the high-ranking males and thus expressed a mate choice based on rank, their overall contribution in initiating copulations and thus influencing male mating success was low. The data on paternity from the population, which always contained 4 adult males, revealed that -males sired the majority (65%) of offspring. We conclude, that male dominance rank is an important determinant of male mating and reproductive success in captive (and presumably wild) chimpanzees and that female mate choice is of minor importance in modulating male reproductive outcome.     

Mating Aggregations and Mating Success in the Flower Thrips, Frankliniella schultzei (Thysanoptera: Thripidae), and a Possible Role for Pheromones

Aggregations of Frankliniella schultzei males were observed on the corollas of Hibiscus rosasinensis and Gossypium hirsutum flowers in southeast Queensland. Aggregations were seen only on the upper surfaces of corollas but may have occurred on other flower parts, which were hidden from view. Conspecific females entered aggregations and a small proportion of them mated [18% (n = 163), H. rosasinensis; 30% (n = 181), G. hirsutum]. Most females (87 and 72%, respectively) that did not mate in aggregations walked to other flower parts. Behavior was difficult to observe on these parts, but mating was sometimes observed there. The number of females that landed within aggregations on the upper surfaces of both H. rosasinensis and G. hirsutum corollas was highly correlated with the number of males (r = 0.88, r = 0.93, respectively; P < 0.001). Significantly more mating pairs were observed in high-density aggregations (mean ± SE, 1.10 ± 0.22 and 4.44 ± 0.48, respectively) than in low-density aggregations (0.37 ± 0.11 and 1.67 ± 0.29, respectively)(P < 0.05) on flowers of both species. More F. schultzei females were attracted to sticky traps baited with live conspecific males set among flowering Ipomoea indica(mean ± SE, 8.83 ± 0.32) and G. hirsutum (10.90 ± 0.79) plants than to control traps (0.10 ± 0.05 and 0.70 ± 0.25, respectively) (P < 0.05), presumably in response to male-produced pheromones. Significantly more females were attracted to traps with high male densities than to traps with low densities. We found no statistical evidence that aggregation size influenced mating success (proportion males that mated). Mating success, however, should be evaluated with respect to mating on all flower parts and not just the upper surfaces of corollas. The results of this study constitute the first behavioral evidence for an attractant sex pheromone in thrips.     

Precopulation Sexual Selection in Nysius huttoni White (Heteroptera: Lygaeidae) in Relation to Morphometric Traits

Nysius huttoni White is a polygamous bug, endemic to New Zealand, and an important pest of wheat and brassicas. This bug has a female-biased sexual size dimorphism but relative to body length, males have longer antennae, suggesting that the allometric scales of antennal–body relationships may be highly selective in sexual selection. Body weight and most morphometric traits measured have no effect on mating success of either sex. Males significantly preferred mating with females having thicker abdomens, more mature eggs, and longer ovipositors. This result suggests that males may select their mates on the basis of immediate reproductive benefit: fertilizing more eggs and ensuring better survival of these eggs. Males with large genital structures have mating advantages over those with small ones, suggesting that precopulation sexual selection in this species act on male genital traits rather than body weight and nonsexual traits. Finally, females significantly preferred males with greater slopes for the antennal-body relationship for mating. The allometry in the male antennal length may be an indicator of male reproductive fitness.     

Morphometric variation in theAlonsoa meridionalis complex (Scrophulariaceae)

Morphological field studies of 27 populations of theA. meridionalis complex were conducted in Ecuador. It is possible to distinguish four different form series by the position of the stamens in relation to the style. This trait was congruent with the overall morphometric variation, shown by the results of a canonical discriminant analysis (CDA). The taxonomy of the species complex is discussed based upon the results of the CDA. The degree of outcrossing varied in different form series, from a comparatively high degree of selfing to predominantly outcrossing, as indicated by the variation within relative to among populations. This is probably due to the varying potentials for self-deposition owing to differences in the degree of herkogamy.     

Size Assortative Mating and Reproductive Success of the Funnel-Web Spider, Agelena limbata (Araneae; Agelenidae)

Field observations and laboratory experiments were conducted to assess the relation between male size and reproductive success in the funnel-web spider, Agelena limbata Thorell (Agelenidae), in 2 years. In this species, the body size of males is similar to that of females. In the field, size assortative mating occurred in both years. In 1 year, partial correlation coefficient analysis indicates that male cephalothorax width is a beter predictor of the copulated female cephalothorax width than of the date of pairing. In laboratory experiments, females tended to reject courting males that were smaller in relative body size, and males that were larger in relative body size had greater copulation success. Consequently female rejection of smaller courting males has some contribution to size assortative mating. Since larger females deposited more numerous eggs in the field, larger males are expected to have a higher reproductive success.     

Mating tactics and courtship behavior inCleogonus rubetra (Fabricius) (Coleoptera: Curculionidae)

Females of the tropical weevilCleogonus rubetra oviposit into fruits of the leguminous treeAndira inermis, and larvae develop in the pulp and seed of these fruits. We hypothesized three alternative tactics by which males might secure matings. By using focal observations of males and by evaluating predictions specific to each hypothesis, we demonstrate that males search within aggregations of conspecifics for receptive females, and upon finding a suitable partner, males mount and perform courtship behavior consisting of stroking the eyes and sides of the female's abdomen. Males also stridulate and emit a sequence of short buzzing sounds. While mounted, males actively prevent rival males from mating with their partner. Males defend their mates for a mean duration of 3.7 h (including copulation). As predicted, paired males were larger than solitary individuals, although the difference was marginally nonsignificant. The overabundance of fruits relative to males, the prolonged period during which females are active, and the probability of last male sperm precedence are factors that may have contributed to the evolution of this female-defense tactic by males. Paired females were significantly larger than solitary females. We observed no competition among females for mates, and the correlation between elytron length of paired males and females was not significant.     

A Comparative Analysis of Mating Recognition Signals in Graylings: Hipparchia statilinus vs. H. semele (Lepidoptera: Nymphalidae, Satyrinae)

Courtship is an important character linked to fitness and can evolve in response to female mate choice, to ensure sex identity and quality of a potential mate. It can also be a major pre-mating isolating mechanism in butterflies and many other species. In this paper, aspects of the reproductive behaviour of Hipparchia statilinus are described. First, the ethogram and the sequential structure of courtship leading to copulation and female refusal behaviour are showed; second, the results are compared with the behaviour of the sympatric and syntopic species, H. semele. Sequential analysis of H. statilinus courtship showed that, once a male has started the sequence, the following steps most likely follow up to the end. Courtship seems to reflect female behaviour: the male can repeat the whole sequence or part of it more than once, waiting for female signals. The general pattern of sexual behaviour in H. semele and in H. statilinus is mainly identical: perching strategy, flight pursuit, courtship. In both species, courtship consists of a highly stereotypic sequence, and differences between sequences are primarily related to presence/absence, order and performance of steps. This study is the first step of an experimental design addressed to a better understanding of mating recognition signals in Hipparchia and provides more details to define the relative roles of phylogeny and environment in shaping boundaries among species.     

Differences in Mating Propensity Between Immature Female Color Morphs in the Damselfly Ischnura elegans (Insecta: Odonata)

Female-limited color polymorphisms occur in a variety of animal taxa where excessive male sexual harassment may explain the coexistence of multiple female color morphs. In the color polymorphic damselfly Ischnura elegans, mature and immature female color morphs coexist at the mating site where males are in search for suitable mating partners. Here, we study male preference and female mating propensity for the two immature female morphs. As would be expected, compared to mature morphs, both immature female morphs mate much less. Within immature females, one morph consistently mates more frequently compared to the other morph, a pattern that is similar for the ontogenetically corresponding mature female morphs. Preference experiments with the two differently colored immature female morphs, however, did not indicate male mate preference for either morph. Low mating frequencies of immature females at natural sites in combination with relatively high attractiveness of immature models in terms of male preference indicate that female behavior influences female mating success.     

Learning and solar orientation in the mole cricket Gryllotalpa gryllotalpa (Orthoptera: Gryllidae)

The ecologically efficient escape direction assumed by Gryllotalpa gryllotalpais learned by the larvae after they leave the maternal nest. Nonetheless, larvae hatched in the laboratory are innately capable of using the sun to maintain a set escape direction. The species can also modify the set point of its sun compass to conform to topographical changes encountered during its wanderings.     

The Influence of Pedipalp Autotomy on the Courtship and Mating Behavior of Pardosa milvina (Araneae: Lycosidae)

Male Pardosa milvina wolf spiders use their pedipalps both for copulation and courtship. Pedipalp loss is significantly more common among adult males compared to females. We measured the courtship and mating effects associated with the loss of one or both pedipalps among adult male P. milvina. Pedipalp loss significantly reduced courtship intensity, but had no influence on mounting success. Intact males were less likely to be cannibalized and suffered fewer predatory attacks by females than autotomized males. Loss of the left pedipalp resulted in significantly less intense courtship, higher female aggression levels, and delayed onset of courtship whereas loss of the right pedipalp minimally affected male and female behavior relative to intact males. Pedipalp displays may function in reducing female aggression rather than increasing female receptivity.     

Acoustic communication in the trilling field cricket,Gryllus rubens (Orthoptera: Gryllidae)

Male field crickets produce calling songs that are used for attracting conspecific females for mating. Acoustic communication was studied in the trilling field cricket, Gryllus rubens.A trilled calling song consists of a continuous train of sound pulses, each of which was repeated at a stereotyped rate. Singing males were recorded at different temperatures. The pulse period of the calling song decreased with increasing temperature; there was less effect of temperature on pulse duration. Female phonotaxis was studied on a noncompensating, spherical treadmill. In two-stimulus (choice) playback experiments, females preferred the conspecific trilled song over the chirped calling song of a sympatric species, Gryllus fultoni.This preference persisted even when the song of G. fultoniwas 6 dB louder. Females also discriminated between synthetic trills having different pulse periods; females chose trills with the conspecific pulse period over trills having lower and higher pulse periods.     

Effects of female deprivation on mating propensity and mate selectivity by maleRequena verticalis (Orthoptera: Tettigoniidae)

This study examined the effects of female deprivation on the mating propensity and size selectivity of male Requena verticalis,an Australian katydid in which males provide a large spermatophylax to females during mating. Specifically, I tested the hypotheses that mating readiness would increase, while mate discrimination would decrease (i. e., females would be accepted independently of their size, an indicator of fecundity) as the period of female deprivation increased. Fieldcaught males were held in isolation for 1, 5, or 14 days in the laboratory and then presented with virgin females. As expected, males held for 5 and 14 days were more likely to mate than males held only a single day. However, in none of the treatments did males discriminate among females on the basis of size. These results are compared with those obtained in a similar study on a zaprochiline katydid.     

Courtship and Mating in the Giant Hairy Desert Scorpion, Hadrurus arizonensis (Scorpionida, Iuridae)

Hadrurus arizonensis is a large, long-lived species of North American desert scorpion with lengthy, stereotyped courtship behaviors that lead to sperm transfer via an external spermatophore. Courtship and mating behaviors in H. arizonensis and other members of the Iuridae family have not been described. H. arizonensis has reproductive behavior similar to that of other scorpions, including the promenade a deux, but with some unique components described here for the first time. Courtship and mating behaviors of H. arizonensis are presented in a flowchart to emphasize its stereotypical nature and suitability for experimental manipulation in field and laboratory studies.