scholarly journals Differential allocation in a gift-giving spider: males adjust their reproductive investment in response to female condition

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Diego Solano-Brenes ◽  
Luiz Ernesto Costa-Schmidt ◽  
Maria Jose Albo ◽  
Glauco Machado

Abstract Background When males are selective, they can either reject low-quality females or adjust their reproductive investment in response to traits that indicate female quality (e.g., body size or condition). According to the differential allocation hypothesis, males increase their reproductive investment when paired with high-quality females (positive differential allocation) or increase their reproductive investment when paired with low-quality females (negative differential allocation). This hypothesis has been proposed for monogamous species with biparental care, and most empirical studies focus on birds. Here we used the polygamous spider Paratrechalea ornata, in which males offer prey wrapped in silk as nuptial gifts, to test whether males adjust their reproductive investment in gift size, pre-copulatory and copulatory courtship, and sperm transfer in response to female body condition. Results Males exposed to females in good body condition added more flies to the gift, stimulated these females longer with abdominal touches during pre-copulatory courtship, and had longer pedipalp insertions than males exposed to females in poor body condition. Female condition affected neither silk investment in nuptial gift wrapping nor the quantity of sperm transferred by males. Finally, females in good body condition oviposited faster after copulation and laid more eggs than females in poor body condition. Conclusions We provide experimental evidence that males of a gift-giving spider exhibit positive differential allocation in three key aspects of their reproductive investment: the size of the nutritious gift, duration of pre-copulatory courtship, and duration of pedipalp insertions, which is regarded as a form of copulatory courtship in spiders. This positive differential allocation is likely associated with the benefits of copulating with females in good body condition. These females are more fecund and oviposit faster after copulation than females in poor body condition, which under natural field conditions probably reduces the risk of multiple matings and thus the level of sperm competition faced by the males. As a final remark, our findings indicate that the hypothesis of differential allocation also applies to species with a scramble competition mating system, in which males heavily invest in nuptial gift construction, but not in parental care.

2020 ◽  
Vol 74 (11) ◽  
Author(s):  
Monika J. B. Eberhard ◽  
Alexandra Machnis ◽  
Gabriele Uhl

Abstract Condition-dependent secondary sexual traits and signals are often crucial for mate choice decisions. Nuptial gifts, provided by the male to the female during mating, may represent an indicator of male condition, especially if production of the gift is energetically costly. Additionally, other signalling modalities may well play a role in mate choice in such systems. Females of the nursery web spider Pisaura mirabilis preferably mate with males that provide a prey item wrapped in silk. Apart from the nuptial gift, vibrational signals employed during courtship and mating may reveal additional information about male condition. We tested condition-dependence of male vibrational signals of well-fed versus starved males, when in contact with female dragline silk and during mating trials. Our results show that vibrational signals are produced in P. mirabilis, both during pre-copulatory courtship and during copulation. Male courtship signals were condition-dependent: males in good condition initiated signalling earlier and emitted more vibrational pulses than poor-condition males. They were also more likely to be accepted by the female for copulation. We additionally identified vibrational signals during copulation. These signals were different from pre-copulatory courtship vibrations but did not differ between the treatment groups. This study shows that vibrational communication plays an important role before and during copulation in P. mirabilis. It sets the stage for further experiments on spider biotremology associated with nuptial gift giving behaviour. Significance statement Male courtship behaviour can indicate a male’s condition and quality and be subject to female mate choice. Vibrational communication during mating plays a crucial role in many animal species. Spiders are known to be extremely sensitive towards vibrations, and there is evidence that vibratory signals are also used during courtship. Here, we study the nuptial gift-giving spider Pisaura mirabilis in which courtship entails providing a nuptial gift by the male to the female. The gift quality determines on the probability and duration of mating. We investigated the role of vibrational behaviour in this species by standardizing nuptial gifts. Our study demonstrates that vibratory signals comprise information about the male’s condition, that signals are also produced during mating and that courtship and copulatory signals are strikingly different. We suggest that vibrational communication provides important condition-dependent traits for female mate choice in addition to the nuptial gift.


2013 ◽  
Vol 280 (1772) ◽  
pp. 20131735 ◽  
Author(s):  
Maria J. Albo ◽  
Trine Bilde ◽  
Gabriele Uhl

Polyandrous females are expected to discriminate among males through postcopulatory cryptic mate choice. Yet, there is surprisingly little unequivocal evidence for female-mediated cryptic sperm choice. In species in which nuptial gifts facilitate mating, females may gain indirect benefits through preferential storage of sperm from gift-giving males if the gift signals male quality. We tested this hypothesis in the spider Pisaura mirabilis by quantifying the number of sperm stored in response to copulation with males with or without a nuptial gift, while experimentally controlling copulation duration. We further assessed the effect of gift presence and copulation duration on egg-hatching success in matings with uninterrupted copulations with gift-giving males. We show that females mated to gift-giving males stored more sperm and experienced 17% higher egg-hatching success, compared with those mated to no-gift males, despite matched copulation durations. Uninterrupted copulations resulted in both increased sperm storage and egg-hatching success. Our study confirms the prediction that the nuptial gift as a male signal is under positive sexual selection by females through cryptic sperm storage. In addition, the gift facilitates longer copulations and increased sperm transfer providing two different types of advantage to gift-giving in males.


Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 310
Author(s):  
Dariusz Krzysztof Małek ◽  
Marcin Czarnoleski

The thermal environment influences insect performance, but the factors affecting insect thermal preferences are rarely studied. We studied Callosobruchus maculatus seed beetles and hypothesized that thermal preferences are influenced by water balance, with individuals with limited water reserves preferring cooler habitats to reduce evaporative water loss. Adult C. maculatus, in their flightless morph, do not consume food or water, but a copulating male provides a female with a nuptial gift of ejaculate containing nutrients and water. We hypothesized that gift recipients would prefer warmer habitats than gift donors and that both sexes would plastically adjust their thermal preferences according to the size of the transferred gift. We measured the thermal preference in each sex in individuals that were mated once or were unmated. In the mated group, we measured the sizes of the nuptial gifts and calculated proportional body mass changes in each mate during copulation. Supporting the role of water balance in thermal preference, females preferred warmer habitats than males. Nevertheless, thermal preferences in either sex were not affected by mating status or gift size. It is likely that high rates of mating and gift transfers in C. maculatus living under natural conditions promoted the evolution of constitutive sex-dependent thermal preferences.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Lidya Gebresilassie ◽  
Berihun Afera Tadele

Background.Haemonchosiscaused byHaemonchus contortusis a predominant, highly pathogenic, and economically important disease of sheep and goats.Objective. Assessing the prevalence ofHaemonchusparasite and its associated risk factors in sheep slaughtered at different restaurants of Wukro.Methods. Cross-sectional study using random sampling from November 2013 to April 2014 in a total of 384 sheep was conducted and SPSS version 20 software using descriptive statistics was used for data analysis andP<0.05was considered significant.Result. The overall prevalence ofHaemonchus contortuswas 40.9% (n=157). The prevalence in medium body condition 27.3% (n=105) varies significantly from that of good body condition 13.5% (n=52) (P<0.05). Moreover, there was significant variation (P<0.05) in the prevalence in young and adult sheep with rates of 21.9% (n=84) and 19% (n=73), respectively. At the same time, there is significant variation (P<0.05) in male and female sheep with prevalence of 29.7% (n=114) and 11.2% (n=43), respectively. The prevalence of 25.3% (n=97) in sheep that originated from Negash compared to Wukro and Agulae showed no significant variation (P>0.05).Conclusion. The current finding revealed that significant numbers of sheep were affected by the parasites. Hence strategic deworming with good husbandry practice should be implemented.


2016 ◽  
Vol 12 (5) ◽  
pp. 20151082 ◽  
Author(s):  
Søren Toft ◽  
Maria J. Albo

Several not mutually exclusive functions have been ascribed to nuptial gifts across different taxa. Although the idea that a nuptial prey gift may protect the male from pre-copulatory sexual cannibalism is attractive, it has previously been considered of no importance based on indirect evidence and rejected by experimental tests. We reinvestigated whether nuptial gifts may function as a shield against female attacks during mating encounters in the spider Pisaura mirabilis and whether female hunger influences the likelihood of cannibalistic attacks. The results showed that pre-copulatory sexual cannibalism was enhanced when males courted without a gift and this was independent of female hunger. We propose that the nuptial gift trait has evolved partly as a counteradaptation to female aggression in this spider species.


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