It is a matter of taste: chemical signals mediate nuptial gift acceptance in a neotropical spider

Nuptial gift offering is a courtship trait found among several insect orders and some spider families. Recent studies indicate that this gift-giving behavior in spiders represents the male mating effort acting on female receptivity through a mechanism of foraging motivation. However, little attention has been given to the sensory channels that are influencing female acceptance. To understand the role of these sensory channels in female perception of a nuptial gift, we focused on the nuptial gift of the neotropical spider Paratrechalea ornata (Araneae, Trechaleidae). The nuptial gift of this species is composed of a prey item wrapped in silk, and previous works suggest that visual and/or chemical cues may be involved in inducing female grasping behavior. We isolated sensory channels using mimetic nuptial gifts (artificial items) or by manipulating real nuptial gifts. Isolated visual signals were not responsible for female acceptance, whereas chemical signals found within the nuptial gift silk layer induced female acceptance. Our findings clearly indicate that a chemical signal located in the silk of the nuptial gift is the main attractant channel, and we formulated 2 hypotheses to explain the mechanisms of action in the female sensory system. We also discuss the consequences of such signaling over female acceptance.

Chemical basis of courtship in a beetle (Neopyrochroa flabellata): Cantharidin as "nuptial gift".

The amount of cantharidin (Spanish fly) that the Neopyrochroa flabellata male presents to the female as a glandular offering during courtship represents only a small fraction of the total cantharidin the male accumulates systemically following ingestion of the compound. A major fraction of the acquired cantharidin is stored by the male in the large accessory glands of the reproductive system. At mating, the male transfers this supply, presumably as part of the sperm package, to the spermatheca of the female. The female in turn allocates the gift to the eggs. Eggs endowed with cantharidin proved relatively invulnerable to attack by a predaceous beetle larva (Coleomegilla maculata).

Reproductive interference between two sibling species of gift-giving spiders

We investigated the possibility of reproductive interference between two sibling spider species, Paratrechalea azul and Paratrechalea ornata, which occur syntopically and reproduce synchronously. Males of both species offer a nuptial gift composed of prey wrapped in silk to females. Through laboratory experiments, we evaluated possible asymmetries in the outcome of heterospecific encounters between males and females, and investigated whether chemical signalling could function as a premating barrier between the two species. Males of P. azul were unable to discriminate conspecific from heterospecific female draglines, which resulted in wasted time and energy in nuptial gift construction. Males of P. ornata incurred a higher cost for discrimination mistakes because most of them were attacked by heterospecific females; 95% lost the nuptial gift upon the attack and 33% were preyed upon. This pattern is probably a consequence of differences in body size between males and females of each species. Both species showed erroneous female choice, but only P. ornata females courted heterospecific males, which are considerably larger than conspecific males and may resemble high-quality mating partners. Males of P. ornata also made discrimination mistakes, but at a much lower frequency compared to P. azul males. The selective pressure for precise recognition of conspecific female signs is probably stronger on P. ornata males because misdirected courtship may increase their chances of encountering predatory heterospecific females. This study provides the first detailed evidence of reproductive interference between two reproductively isolated spider species, showing that the costs paid by individuals of different sexes and different species are highly asymmetric. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Sodium: a male moth's gift to its offspring.

Males of the moth Gluphisia septentrionis acquire sodium by drinking from mud puddles. Analyses of male and female bodies indicate that such "puddling" behavior enables the male to provide his mate with a nuptial gift of sodium, presumably via the spermatophore. This gift (about 10 microg), amounting to more than half of a puddler male's total body sodium, is in large measure apportioned by the female to her eggs. Puddler-sired eggs contain 2 to 4 times more sodium than those control-sired; this difference is already apparent in eggs laid the night after mating. Paternal endowment of offspring with sodium had not previously been demonstrated for an insect to our knowledge. The potential adaptive significance of such chemical bestowal is evident, given that the foliar diet of G. septentrionis larvae is extremely low in sodium content.

The adaptive significance and prevalence of courtship feeding in Hawaiian swordtail crickets

Males of many insect species feed their partner during courtship and mating. Studies of male nutrient donation in various systems have established that nuptial feeding has evolved mostly through sexual selection. Although there is extensive diversity in form, the function of nuptial gifts is typically limited to either facilitating copulation or increasing ejaculate transfer, depending on the time at which the gift is consumed by females. Unlike other insects, the Hawaiian swordtail cricket Laupala (Gryllidae: Trigonidiinae) exhibits serial transfer of nuptial gifts. Males transfer multiple spermless 'micro' spermatophores over several hours before mating at the end of the day (i.e. before the transfer of a single sperm-containing 'macro' spermatophore). By experimental manipulation of male microspermatophore donation, I tested several hypotheses pertaining to the adaptive significance of nuptial gifts in this system. I found that microspermatophore transfer improves insemination, by causing the female reproductive tract to take in more sperm. This result reveals a previously undocumented function for premating nuptial gift donation among insects. Enhanced sperm transfer due to microspermatophore donation may represent male manipulation or an internal mechanism of post-copulatory choice by females. I also performed experimental manipulation of male photoperiod to investigate how time and gender influence nuptial gift production and mating behavior. I found that the timing of mating is limited in males but not females and that the time of pair formation has consequences for the degree of nuptial gift donation, which suggests that both mating timing and microspermatophore number is important for male reproductive success. Finally, I observed the mating behavior of several trigonidiine taxa for a comparative analysis of sexual behavior and found that other genera also utilize spermless microspermatophores, which suggests that microspermatophore donation may be a common nuptial gift strategy among swordtail crickets. The elaborate nuptial feeding behavior of Hawaiian swordtail crickets prior to mating represents a newly discovered strategy to increase male insemination success rather than mating success. Based on this unexpected result, it is worth exploring whether courtship behaviors in other cricket or insect mating systems have also evolved to increase sperm uptake.

Reproductive behavior of Eidmanacris corumbatai garcia (Orthoptera: Phalangopsidae)

Adult males of Eidmanacris corumbatai Garcia have reduced tegmina without stridulatory apparatus. For this reason, they developed other means of intra-specific communication. During courtship, the males use a combination of foreleg drumming and waving of the antennae, in addition to chemical signaling through pheromones. The females become receptive to copulation when the males expose their metanotal gland. This gland, located on the male metanotum, is also a source of substances on which females feed before receiving the spermatophore. During copulation, the female destroys the apex of the metanotal gland to gain access to the secretion released by this structure.

The evolution of mating rates in Pieris napi

In the green-veined white butterfly (Pieris napi), females obtain direct fitness benefits from mating multiply and studies have shown that fitness increases seemingly monotonically with number of matings. The reason is that at mating males transfer a large nutritious gift (a so called nuptial gift) to the females that the females use to increase both their fecundity and lifespan. In addition, if exposed to poor food conditions as larvae, females mature at a smaller size compared to males. Accordingly, it was suggested that smaller females could compensate for their size through nuptial feeding by, for instance, mating more frequently. We did not find any support for that hypothesis. On the contrary, larger females remated sooner and had a higher lifetime number of matings. Neither were smaller females able to compensate in any other way, because singly mated females and multiply mated females suffered to the same extent from their smaller size. This thesis also shows that despite the positive relationship between fitness and number of matings, there is a large variation in female mating frequency in wild populations and about every second female mates only once or twice. This variation is not dependent on how often females get courted by males, because female mating frequency was shown not to be affected by male courtship intensity. Hence, the reason for the low mating frequency could either be that males have evolved the ability to manipulate females to mate at a suboptimal rate as a measure of protection against sperm competition, or alternatively, that female mating rate is suppressed by some costs. Using two selection lines, artificially selected for either a high or a low mating rate, we showed that the variation in mating rate was mainly a female trait because which line the females were from affected their mating rate whereas which line the male was from did not. This implies that females mate at a low rate due to hidden costs or due to constraints. The same study also showed that females with a high "intrinsic" mating rate lived shorter, but only when denied remating. This led us to test the hypothesis that the cost females face is to have the ability to mate at a high rate but the cost is only paid when remating opportunities are scarce. However, we found no support for such an idea, because females with a high intrinsic mating rate held in a cold environment where the butterflies were prevented from flying and feeding did not live shorter. Neither was there an effect of a female’s mating rate on her ability to quickly break down and convert male nutrient gifts into egg material. Female mating rate did, on the other hand, affect dispersal tendency, with low mating rate females being more inclined to fly between different habitats. The underlying reason for this is still to be explored.

An Argument against immediately repealing the laws which treat the nuptial bond as indissoluble /

Mode of access: Internet.

Sale of property gifted under a will by an attorney acting under an enduring power of attorney : does the gift adeem and what is the attorney's duty?

The authors examine Moylan v Rickard and how the case illustrates the effectiveness of the Powers of Attorney Act 1998 (Qld) to provide remedies and other possible avenues of redress

Give and take in major gift relationships

This article investigates the complex phenomenon of major gift giving to charitable institutions. Drawing on empirical evidence from interviews with 16 Australian major donors (who gave a single gift of at least AU$10,000 in 2008 or 2009), we seek to better understand donor expectations and (dis)satisfaction. Given growing need for social services, and the competition among nonprofit organisations (NPOs) to secure sustainable funding, this research is particularly timely. Currently, little is known about major donors’ expectations, wants and needs. Equity theory, with the concept of reciprocity at its core, was found to provide a useful framework for understanding these phenomena. A model of equitable major gift relationships was developed from the data, which portrays balanced relationships and identifies potential areas of dissatisfaction for major donors. We conclude by offering suggestions for NPOs seeking to understand the complexities of major gift relationships, with practical implications for meeting donors’ needs.

Perceptions of charities and the ultimate gift : the use of the Repertory Test to elicit salient bequest decision criteria

This paper reports a practitioner/academic collaboration that sought to identify the attributes salient in the decision-making process of individuals considering a charitable bequest in Australia. Philanthropy scholars concur that bequest making behaviour is generally not well understood or researched and is fertile terrain for new enquiry. They urge scholars and practitioners to integrate learning from other relevant disciplines to reveal new insights and understandings into why so many individuals elect to make a testamentary gift to a charity in their will or other planned giving instrument. This research draws on the branding literature; and effectively trialed the use of Kelly’s (1955) Repertory Test from clinical psychology, the results of which will provide researchers and charity marketing practitioners with an enhanced understanding of bequest decision criteria.

Charitable bequests a specific case of gift giving

Over the last 5 years, charities have acknowledged that bequests are a source of income with the potential for enormous growth. As the population ages the number of possible bequest donors will increase. Charities are implementing bequest campaigns to target the older donors, and the need for research is evident...

Who claims gifts as a tax deduction? An examination of tax deductible gift statistics

Many donors, particularly those contemplating a substantial donation, consider whether their donation will be deductible from their taxable income. This motivation is not lost on fundraisers who conduct appeals before the end of the taxation year to capitalise on such desires. The motivation is also not lost on Treasury analysts who perceive the tax deduction as “lost” revenue and wonder if the loss is “efficient” in economic terms. Would it be more efficient for the government to give grants to deserving organisations, rather than permitting donor directed gifts? Better still, what about contracts that lock in the use of the money for a government priority? What place does tax deduction play in influencing a donor to give? Does the size of the gift bear any relationship to the size of the tax deduction? Could an increased level of donations take up an increasing shortfall in government welfare and community infrastructure spending? Despite these questions being asked regularly, little has been rigorously established about the effect of taxation deductions on a donor’s gifts.