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

Abstract

Male delivering of a prey packed in silk as a nuptial gift is rare in spiders and restricted until now to Pisauridae. Here, we describe this behavioral pattern found in two Trechaleidae species, Paratrechalea azul Carico 2005, and Paratrechalea ornata (Mello-Leitão 1943), mainly based on field observations. We observed the following steps of sexual behavior: sperm induction, nuptial gift construction, mate searching, pre-copulatory courtship, copulation, and copulatory ending. In this group, a nuptial gift consists of a prey wrapped in silk, which appears as a white rounded shape. The male carries his nuptial gift in his chelicerae while searching for a female. When he finds a female, he shows a stereotyped courting behavior consisting of a hyperflexed posture that is also assumed by the receptive female while they face each other. The copulatory position and pattern is similar to that found in other Lycosoidea: the male mounts the female and makes a total of four palpal insertions while alternating sides. However, after each palpal insertion the male dismounts and returns to a frontal position while biting the gift. Copulatory courtship is evidenced by palpal and leg movements. The copulation ends by female initiative and she almost always retains the nuptial gift. No case of pre-copulatory or post-copulatory cannibalism has been recorded. Descriptions of nuptial gift construction by males and copulation in these species, as well as hypotheses about the origin of nuptial gift construction among spiders, are presented. These descriptions are the first records of such nuptial gift offering for Neotropical spiders and for non-Pisauridae species as well.

Cryptic Female Choice and Nuptial Prey Gifts in a Spider Model

“…mirabilis and Pa. ornata. The similarities between their reproductive behaviors suggest a strong phylogenetic influence in their evolutionary path (Costa-Schmidt et al 2008;Albo et al 2014a), although such interpretation lacks a formal analytical demonstration. The standard mating behavior for these two species is briefly described in the diagram provided in (Table 6.1).…”

“…mirabilis, but a closer look toward the Pisauridae family resulted in a list of species incorporating this same behavioral strategy into their courtship repertoire (Nitzsche 1988;Itakura 1993Itakura , 1998Bastos-Pereira 2009;Nitzsche 2011). Since the description of some new records for the Trechaleidae family (Costa-Schmidt et al 2008;Silva and Lise 2009), prey gifts turned into a common reproductive strategy within these two families from the Lycosoidea clade. Within the Trechaleidae family, Paratrechalea ornata (Mello-Leitão 1943) (Carico 2005) is being the subject of intensive evolutionary studies regarding the adaptive interpretation of prey gift as a sexually selected trait.…”

“…6.1e). The external silk layer offers to males a better control of the copula, by allowing them to access the female reaction during the sperm transfer by holding the prey gift with the third leg pair (Costa-Schmidt et al 2008;Nitzsche 2011). The inner content seems to be responsible for the main effect of prey gifts is in terms of copula duration, which seems to be associated to both the quality and the size of the inner content (Bruun et al 2004;Albo and Costa 2010;Albo et al 2011;Klein et al 2014).…”

“…We can take the premise that the more modified or complex the nuptial gift, the more information it contains. Let us take as an example a special class of nuptial gifts within spiders, the prey gifts (see Prey gifts section for a definition): It may consist of nothing but the prey, or may be also covered by a layer of silk that may be used as a source of information between males and females, or at least as a substrate for information exchange (Costa-Schmidt et al 2008;Bilde et al 2007;Brum et al 2012). Certainly, the chance that this character will be used as a source of information for CFC is higher the more complex it is.…”

Primer registro de un regalo nupcial en Trechalea amazonica (Araneae, Lycosoidea, Trechaleidae)

“…Later, this behavior was described in detail after field observations made by Costa-Schmidt et al (2008), for Paratrechalea azul Carico, 2005 andP. ornata (Mello-Leitão 1943), in Maquiné, Southern Brazil.…”