The function of nuptial feeding in insects: a review of empirical studies

Abstract

Nuptial feeding encompasses any form of nutrient transfer from the male to the female during or directly after courtship and/or copulation. In insects, nuptial gifts may take the form of food captured or collected by the male, parts, or even the whole of the male's body, or glandular products of the male such as salivary secretions, external glandular secretions, the spermatophore and substances in the ejaculate. Over the past decade, there has been considerable debate over the current function of nuptial feeding in insects. This debate has centred on the issue of whether nuptial gifts function as paternal investment (i.e. function to increase the fitness and/or number of the gift-giving male's own offspring) or as mating effort (i.e. function to attract females, facilitate coupling, and/or to maximize ejaculate transfer), although the two hypotheses are not mutually exclusive. In the present article, evidence for the potential of nuptial gifts to function as either paternal investment, mating effort, or both is reviewed for each form of nuptial feeding in each insect taxon for which sufficient data are available. Empirical evidence suggests that many diverse forms of nuptial feeding in different insect taxa function, at least in part, as mating effort. For example, nuptial prey and salivary masses in the Mecoptera, regurgitated food in Drosophila (Diptera), hind-wing feeding in Cyphoderris (Orthoptera) and the secretion of the male's cephalic gland in Neopyrochroa (Coleoptera) and Zorotypus (Zoraptera) appear to function to entice females to copulate and/or to facilitate coupling. Nuptial prey and salivary masses in the Mecoptera also appear to function to maximize ejaculate transfer (which is also a form of mating effort), as do nuptial prey in Empis (Diptera), external glandular secretions in Oecanthus and Allonemobius (Orthoptera) and the spermatophylax in gryllids and tettigoniids (Orthoptera). Large spermatophores in, for example, the Lepidoptera and Coleoptera, also appear to be maintained by selection on the male to maximize ejaculate transfer and thereby counter the effects of sperm competition. In contrast to the large amount of evidence in support of the mating effort hypothesis, there is a relative lack of good evidence to support the paternal investment hypothesis. Certain studies have demonstrated an increase in the weight and/or number of eggs laid as a result of the receipt of larger gifts, or a greater number of gifts, in tettigoniids, gryllids, acridids, mantids, bruchid beetles, drosophilids and lepidopterans. However, virtually all of these studies (with the possible exception of studies of the spermatophylax in tettigoniids) have failed to control adequately for hormonal substances in the ejaculate that are known to affect female reproductive output. Furthermore, in at least four tettigoniids (but not in the case of two species), three lepidopterans, a drosophilid and probably also bruchid beetles and bittacids, evidence suggests that the male has a low probability of fertilising the eggs tha...

Nuptial gifts and sexual behavior in two species of spider (Araneae, Trechaleidae, Paratrechalea)

“…Possible explanations for the adaptive significance of nuptial gifts within Paratrechalea Four hypotheses explaining the adaptive significance of nuptial gifts in arthropods were introduced previously (Stålhandske 2001(Stålhandske , 2002Sakaluk 2000;Bilde et al 2007;Vahed 1998Vahed , 2007. The first hypothesis is related to paternal investment resulting from natural selection (Vahed 1998;Stålhandske 2001).…”

“…Nuptial gift offering during courtship and mating is well known in arthropods, particularly in insects (Vahed 1998). Three hypotheses for the evolutionary origin of nuptial gifts are usually considered: male investment in his brood, male mating effort, and cannibalism defense (Vahed 1998;Sakaluk 2000;Stålhandske 2001;Bilde et al 2007).…”

“…Three hypotheses for the evolutionary origin of nuptial gifts are usually considered: male investment in his brood, male mating effort, and cannibalism defense (Vahed 1998;Sakaluk 2000;Stålhandske 2001;Bilde et al 2007). Each of these hypotheses seem to have more influence in some systems than in others, even though they do not exclude one another (Stålhandske 2001) and, as said by Bilde et al (2007), all of them assume that females receive direct benefits from the nuptial gift.…”

Chemical defense of the ladybird beetle Epilachna paenulata

“…Alternatively, the alkaloid load in the eggs may not originate only from the female. In several insects the male passes a nuptial gift to the female during copulation (Vahed 1998). Females in turn endow their eggs partially with materials from that gift (Eisner et al 2002;Vahed 1998).…”

“…In several insects the male passes a nuptial gift to the female during copulation (Vahed 1998). Females in turn endow their eggs partially with materials from that gift (Eisner et al 2002;Vahed 1998). We are currently conducting experiments with labeled alkaloid precursors to discern if this holds true for E. paenulata.…”