Natural History, Courtship, Feeding Behaviour and Parasites ofTheridion evexum(Araneae: Theridiidae)

Abstract

Theridion evexum constructs webs in the understory of wet middle-elevation forests in Costa Rica. The spiders construct retreats by curling a leaf and produce a mesh in front of the opening. Long, more or less vertical viscid lines extend from the mesh, and are attached to other leaves. The spiders feed on a large variety of prey (e.g. flies, beetles, earwigs, centipedes), indicating that both flying and walking arthropods are trapped in their webs. The wrapping threads have large viscid globules that rapidly disperse on the prey's surface, forming a thin film. Adult males guard subadult females in their retreats, possibly waiting for them to moult and copulate. As part of courtship, the male places his pedipalps several times on the female's mouthparts, then one pedipalp on her mouthparts and the other on her epigynum before insertion. Eggs were parasitised by Baeus (Scelionidae) and juveniles and subadults by Zatypota petronae (Ichneumonidae). Eggs were eaten by Argyrodes sp. (Theridiidae), and Solenopsis ants stole prey accumulated in the retreats and attacked spiderlings and older juveniles.

A revised and dated phylogeny of cobweb spiders (Araneae, Araneoidea, Theridiidae): A predatory Cretaceous lineage diversifying in the era of the ants (Hymenoptera, Formicidae)

“…Cobweb 81 spiders have long served as models in the study of evolution of 82 sociality (Aviles, 1997;Lubin and Bilde, 2007), containing over half 83 of all social spiders in three of its genera: Theridion Walckenaer, 84 1805 , Parasteatoda Archer, 1946 (Lubin, 85 1995), and especially Anelosimus Simon, 1891 (Aviles et al, 2000;86 Aviles and Purcell, 2011;Aviles and Salazar, 1999;Aviles and 87 Tufino, 1998). Cobweb spiders are also the subjects of study on a 88 range of other topics such as web architecture (Barrantes and 89 Eberhard, 2010; Barrantes and Weng, 2007;Eberhard, 1979, 90 1981; Eberhard et al, 2008aEberhard et al, , 2008bJorger and Eberhard, 2007), 91 morphology (Agnarsson, 2004;Coddington, 1989;Knoflach and 92 Pfaller, 2004), kleptoparasitism (Agnarsson, 2003b;Cangialosi, 93 1990aCangialosi, 93 , 1990bGrostal and Walter, 1997), myrmecophagy 94 (Eberhard, 1979), extraordinary sexual behavior (Knoflach and 95 van-Harten, 2001;Knoflach and van Harten, 2000) and many 96 others. For a comparative analyses of any of these intriguing traits 97 up-to-date phylogenetic analyses are essential (Agnarsson et al, 98 2006(Agnarsson et al, 98 , 2007aAgnarsson and Coddington, 2008;Eberhard et al, 99 2008a; Samuk and Aviles, 2013;Samuk et al, 2012).…”

Oviposition behaviour by a spider‐ectoparasitoid, Zatypota maculata, exploits the specialized prey capture technique of its spider host

“…Zatypota petronae Gauld, 1991 utilizes Theridion evexum Keyserling, 1884 found in Costa Rica (Barrantes & Weng, ). The web of T. evexum includes a folded live leaf that forms a conical retreat, with a tangle in front of the retreat opening, and long viscid lines extending from the tangle to other leaves (Fig.…”

Incidence of Parasitoids and Predators on Eggs of Seven Species of Therididae (Araneae)

“…T. sisyphoides build their domed-sheet webs on isolated treelets and bushes with rigid leaves for web building, primarily in open areas (Madrigal-Brenes & Barrantes 2009), and P. tesselata construct their sheet webs on similar plants, also in open areas, and often in colonies (Eberhard 1972;Barrantes & Weng 2006). T. evexum construct their webs on undergrowth herbs and bushes of secondary and mature forests, and the webs consist of a retreat built by a folded leaf from which the spider lays straight sticky threads that it attaches mostly to leaves and twigs below the retreat (Barrantes & Weng 2007).…”

“…Some araneids build an egg sac and then use a thread to hang it from their web (Hieber 1992b). In the family Theridiidae, many species construct different types of retreats with silk, plant debris, remnants of prey, or 1932; Bristowe 1958; Barrantes & Weng 2007).…”