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In the gift-giving spider Paratrechalea ornata, females mate multiple times and apparently may bias the paternity according to the nuptial gift content (nutritive or worthless). Paternity studies using microsatellite markers would, therefore, be ideal for studying male fertilization success for female offspring. We genotyped four microsatellites previously reported in one species of the genus using 43 individuals from four different localities in Uruguay. We describe the allelic and genotypic variation in all loci, and compare the findings to the reported variation for the genus. Except for one locus, all loci showed significant departure from the Hardy-Weinberg equilibrium due to heterozygote deficit. This could possibly be explained by the mixed nature of the sample and the effect of the population structure. These loci, and especially those that are highly hypervariable, are an important tool for paternity assessment and would allow a better understanding of the role of post-copulatory processes in P. ornata. [ABSTRACT FROM AUTHOR]

Abstract Background Polyandry is commonly maintained by direct benefits in gift-giving species, so females may remate as an adaptive foraging strategy. However, the assumption of a direct benefit fades in mating systems where male gift-giving behaviour has evolved from offering nutritive to worthless (non-nutritive) items. In the spider Paratrechalea ornata, 70% of gifts in nature are worthless. We therefore predicted female receptivity to be independent of hunger in this species. We exposed poorly-fed and well-fed females to multiple males offering nutritive gifts and well-fed females to males offering worthless gifts. Results Though the treatments strongly affected fecundity, females of all groups had similar number of matings. This confirms that female receptivity is independent of their nutritional state, i.e. polyandry does not prevail as a foraging strategy. Conclusions In the spider Pisaura mirabilis, in which the majority (62%) of gifts in nature are nutritive, female receptivity depends on hunger. We therefore propose that the dependence of female receptivity on hunger state may have evolved in species with predominantly nutritive gifts but is absent in species with predominantly worthless gifts.

Background: Polyandry is commonly maintained by direct benefits in gift-giving species, so females may remate as an adaptive foraging strategy. However, the assumption of a direct benefit fades in mating systems where male gift-giving behaviour has evolved from offering nutritive to worthless (non-nutritive) items. In the spider Paratrechalea ornata, 70% of gifts in nature are worthless. We therefore predicted female receptivity to be independent of hunger in this species. We exposed poorly-fed and well-fed females to multiple males offering nutritive gifts and well-fed females to males offering worthless gifts. Results: Though the treatments strongly affected fecundity, females of all groups had similar number of matings. This confirms that female receptivity is independent of their nutritional state, i.e. polyandry does not prevail as a foraging strategy. Conclusions: In the spider Pisaura mirabilis, in which the majority (62%) of gifts in nature are nutritive, female receptivity depends on hunger. We therefore propose that the dependence of female receptivity on hunger state may have evolved in species with predominantly nutritive gifts but is absent in species with predominantly worthless gifts. [ABSTRACT FROM AUTHOR]

Males from gift-giving species attempt to obtain food to offer to females. Therefore, food access may affect both their body condition and their reproductive success. In some species, males reduce the costs associated with giving gifts by reusing gifts, or by offering inedible items. Males from the spider Paratrechalea ornata (Trechaleidae) offer fresh prey or ‘genuine gifts’ to females, but also offer prey leftovers or ‘worthless gifts’. We examined gift weight and content, and their relation to male condition in the field. We also investigated how gift content, male condition and female reproductive status (virgin/mated) affect male mating success. In the field, most gifts were worthless; genuine gifts were heavier than worthless ones; and gift weights (both genuine and worthless gifts combined) were positively correlated with male condition. In the laboratory, males in good condition had higher mating success than males in poor condition. Males offering gifts (genuine or worthless) to virgin females enjoyed similar mating success and duration; neither differed significantly when compared to males without gift. In contrast, mated females behaved differently. Males without gifts were consistently rejected by mated females, while those that offered worthless gifts achieved matings. The interplay between male condition, prey access, female mating history and female preferences for gifts can favour the evolution of worthless gifts under certain conditions. Females do not penalize males with non-nutritive items by not mating or by reducing mating duration, but penalties may be potentially exerted via postcopulatory process. [Copyright &y& Elsevier]

An extensive diversity of nuptial gifts is known in invertebrates, but prey wrapped in silk is a unique type of gift present in few insects and spiders. Females from spider species prefer males offering a gift accepting more and longer matings than when males offered no gift. Silk wrapping of the gift is not essential to obtain a mating, but appears to increase the chance of a mating evidencing a particularly intriguing function of this trait. Consequently, as other secondary sexual traits, silk wrapping may be an important trait under sexual selection, if it is used by females as a signal providing information on male quality. We aimed to understand whether the white color of wrapped gifts is used as visual signal during courtship in the spider Paratrechalea ornata. We studied if a patch of white paint on the males' chelicerae is attractive to females by exposing females to males: with their chelicerae painted white; without paint; and with the sternum painted white (paint control). Females contacted males with white chelicerae more often and those males obtained higher mating success than other males. Thereafter, we explored whether silk wrapping is a condition-dependent trait and drives female visual attraction. We exposed good and poor condition males, carrying a prey, to the female silk. Males in poor condition added less silk to the prey than males in good condition, indicating that gift wrapping is an indicator of male quality and may be used by females to acquire information of the potential mate. [ABSTRACT FROM AUTHOR]

In many species the function and evolution of nuptial gifts have been explained by the male mating effort hypothesis; i.e., males increase their fertilization success by donating gifts to females. The gift size may determine copulation duration and consequently affects male fertilization rate. In the well-known spiderPisaura mirabilis, previous studies suggested that the brightness of the gift (a prey wrapped in silk) affects female acceptance and larger gifts promote longer matings, but little is known from other gift-giving spider species. In this paper we test if gift size affects mating and remating success in the Neotropical and semi-aquatic spiderParatrechalea ornata(Trechaleidae). We exposed virgin females to males offering one fly (OF group) or four flies (FF group) wrapped in silk, and afterwards mated females were exposed to remating. Males from FF showed both longer courtship and mating than males from OF. We found a positive linear relationship between insertion duration of male intromittent organs (during which sperm transfer occurs) and mating duration in both groups. Mated females were more reluctant to mate than virgin females, but contrary to our prediction, gift size and mating duration did not seem to influence remating success. Our findings show that large gifts prolong mating duration inP. ornata, supporting the mating effort hypothesis. Females would favour polyandry to gain direct benefits from the gifts, while males may improve success in sperm competition by inducing female reluctance for remating. [ABSTRACT FROM AUTHOR]

The occurrence of nuptial gifts is rare in spiders, being well known only for a single species, Pisaura mirabilis (Pisauridae), whose males offer females a prey wrapped in silk during courtship. Although some males can mate without offering a prey, the gift in this species is thought to represent male mating effort. Male gift offering has been recently described in Paratrechalea ornata, a Neotropical spider belonging to another family, Trechaleidae. We investigated the function of the gift in this species by testing the mating effort hypothesis and two other nonexclusive hypotheses, sexual cannibalism avoidance and paternal investment. Two groups of males were exposed to virgin females: 23 males with no prey (NP group) and 21 males carrying a prey (CP group). Mating success, courtship, copulation and first oviposition were recorded. Males from group CP had better mating success, longer copulations and longer palpal insertions than those from NP. Longer copulations were associated with earlier eggsac construction and oviposition. Some unmated males from NP wrapped prey carrion when they returned to their breeding jars after the trial. Our findings suggest that nuptial gift giving represents male mating effort for P. ornata. Nuptial gifts would allow males to control copulation duration and to accelerate female oviposition, improving sperm supply and paternity, and minimizing possible costs of remating with polyandrous females. [Copyright &y& Elsevier]

By wrapping prey and offering it as a nuptial gift, males can obtain mating and/or parental benefits despite some costs. Males of the Neotropical semiaquatic spider Paratrechalea ornata (Trechaleidae) offer females a nuptial gift consisting of a prey item wrapped in silk. What stimulus inhibits males from feeding and elicits gift construction? We hypothesized that signals associated with female silk threads could affect decision-making by males. We investigated three groups of males carrying a captured prey under different experimental treatments. In the treatment S, males were exposed to an arena with female silk; in SF, males were exposed to both silk and a female confined in a cell, and in the control group, males were exposed to a clean arena. Gift construction was observed only in the S and SF groups, with a similar occurrence rate. After touching females (SF group), males did not change their pattern of gift construction. Gift construction occurrence increased with male and female age. The results lead us to assume that the existence of chemical cues associated with female silk elicits male searching behaviour and gift construction, allowing males to decide between eating or wrapping prey according to the possibility of a sexual encounter. Anticipating gift construction, males are ready to mate, diminishing the risks of predation, female desertion or male–male scramble competition. The effect of age on behavioural variation and the rate of construction is discussed. [ABSTRACT FROM AUTHOR]

For many spiders, sex pheromones associated with female silk are important stimuli that elicit male searching and courtship behaviors. In that context, female sexual receptivity and chemical attractiveness can depend on age and reproductive status. In Paratrechalea ornata (Mello-Leitão 1943) (Araneae: Trechaleidae), males offer females a nuptial gift (a prey wrapped in silk) during courtship. Gift construction is elicited by the presence of female silk, and silk attractiveness is influenced by female age, increasing from 20 days after the female reaches adulthood. Our goal was to investigate whether female age affects female sexual receptivity and to discuss the relationship between receptivity and silk attractiveness. We exposed 26 virgin females, from 2 to 28 days after the final molt, to males offering a nuptial gift. Female sexual receptivity was age dependent and increased with adult female age. Females over 15 days from adulthood accepted more gifts than younger females, but the latency of female gift acceptance was not affected by female age. Female sexual receptivity is synchronized with chemical attractiveness, suggesting that females' pheromone release is adjusted at a particular mating age. We suggest that young virgin females may invest more in foraging and maturing gonads than in mating, accounting for the delay in receptivity and chemical attractiveness. [ABSTRACT FROM AUTHOR]