Females of a gift-giving spider do not trade sex for food gifts: a consequence of male deception?

Irene Pandulli-Alonso,Maria J Albo,Agustín Quaglia

doi:10.1186/s12862-017-0953-8

Abstract

BackgroundPolyandry 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.ResultsThough 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.ConclusionsIn 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.

Highlights

Polyandry is commonly maintained by direct benefits in gift-giving species, so females may remate as an adaptive foraging strategy
We propose the general hypothesis that, all else equal, female receptivity depends on hunger in mating systems with mostly nutritive gifts but not in mating systems with a majority of worthless gifts
We verified that as consequence of the food received via matings (1 fly gift per mating) and the daily feeding regimen (10 fruitflies per day) in relation to the number of experiments, the total food events by females was different among groups: Well fed-Nutritive gift (2.59 ± 0.05) > Well fed-Worthless gift (1.97 ± 0.01) > Poorly fed- Nutritive gift (0.58 ± 0.04) (GLM (p): X22, 63 = 438.93, p < 0.0001)

Summary

Introduction

Polyandry is commonly maintained by direct benefits in gift-giving species, so females may remate as an adaptive foraging strategy. 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. Due to different adverse factors resulting in limited food availability or low body condition, males may not be able to provide the goods that females prefer. Instead, they may maximize their success by reducing their costs, e.g. by deception [13, 14].

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Results

Discussion

Conclusion