Arachnologische Mitteilungen 55

Arachnologische Mitteilungen / Arachnology Letters 55: 30-35 Karlsruhe, April 2018 A large number of parasites drastically change host behaviour which increases parasite survivorship, dispersal, and repro- duction (Helluy & Holmes 2005). Among spider parasitoids, all wasp species in the Polysphincta genus group (Ichneumo- nidae: Pimplinae) are koinobiont ectoparasitoids, which lay a single egg on the dorsum of the anterior section of the spider opisthosoma (Nielsen 1923).When the larva emerges, it bites through the spider cuticle to feed on the hemolymph, remai- ning attached to the spider to the last instar (Nielsen 1923, Eberhard 2000). Hours before moulting to the last instar, the larva induces the spider to construct a modified web (cocoon web), which provides protection to the cocoon that the last- instar larva constructs (Eberhard 2001, Weng & Barrantes 2007, Gonzaga et al. 2015, Korenko 2016). The cocoon webs constructed by spiders under the influ- ence of polysphinctines vary widely across different spider species (Gonzaga & Sobczak 2007, Weng & Barrantes 2007, Gonzaga et al. 2010, Barrantes et al. 2017), and often within the same spider species (Eberhard 2001, 2013).This variation correlates with the design and structure of the normal web. With few exceptions (Gonzaga et al. 2016), in normal webs with a retreat for the spider’s protection, or in long-lived webs, the cocoon web induced by the parasitoid tends to be more similar to the normal web, than in cocoon webs of spiders that normally build short-lived, exposed webs (Eberhard 2000, Weng & Barrantes 2007, Korenko 2017). Within this group of ectoparasitic wasps, those in the ge- nus Hymenoepimecis are known to attack orb-web spiders in two different families (Araneidae and Tetragnathidae). Our aim here is to describe the cocoon web and behaviour of the larva of H. heidyae (Gauld, 1991) parasitizing the araneid Kapogea cyrtophoroides (F. O. P.-Cambridge, 1904). The only previous information on this interaction consists of the de- scription of a single individual of H. heidyae reared by W. G. Eberhard (in Gauld 2000) from Cyrtophora nympha (= K. cyr- tophoroides ). In this case, the spider host was provided with some twigs in which the larva induced the spider to build a small tangle in whose centre the larva built its cocoon (W. Eberhard pers. comm.), but no further behavioural observa- tions were taken. The web of K. cyrtophoroides consists of a dense, nearly horizontal, orbicular web that has a large number of primary and secondary radii and a large number of very closely spaced non-sticky spiral loops (Levi 1997). It also includes a den- se tri-dimensional thick tangle of threads above and below the horizontal web (Fig. 1a).The tangles support the orb, and probably also function to knock down prey onto the sheet as well as to defend the spider against attacks from below.Thus, considering the characteristics of the Kapogea web, we expect the changes induced by H. heidyae on the spider’s cocoon web to be small, as observed in cocoon webs of the related ge- nus Manogea (Sobczak et al. 2009) and other long-lived webs (Korenko 2017). Material and methods We collected the parasitized spiders at La Tirimbina Biological Reserve, Sarapiquí, Heredia province (10.4333°N, 83.9833°W; 150 m a.s.l.), Veragua Rainforest Eco Adventure (9.9167°N, 83.1833°W; 350 m a.s.l.) and the Indigenous Reserve Kéköl­ di, Talamanca (9.6325°N, 82.7867°W; 280 m a.s.l.), both in Limón province; all three sites are on the Caribbean slope of Costa Rica.The mean annual temperature ranges from 25.3 °C When a little is enough: cocoon web of Kapogea cyrtophoroides (Araneae: Araneidae) induced by Hymenoepimecis heidyae (Ichneumonidae: Pimplinae) Gilbert Barrantes, Laura Segura-Hernández, Diego Solano-Brenes & Paul Hanson doi: 10.30963/aramit5505 Abstract. The final instar larvae of the koinobiont ectoparasitoids in the Polysphincta group of genera induce their host spiders to con- struct webs that protect the wasp pupa during its development. It has been hypothesized that changes in structure and design in the cocoon web correlate with the duration and characteristics of the normal web. Kapogea cyrtophoroides (Araneidae) construct long-lived, strong normal webs; the cocoon web induced by Hymenoepimecis heidyae (Ichneumonidae) is nearly identical to the normal web, pro- viding support for the hypothesis. The larva constructs its cocoon in the centre of the host’s dense web, connecting it to the spider web and following the same behavioural pattern of construction described for other wasp species in the same group. The behaviour induced in the spider as well as the cocoon construction is very stereotypic, and consistent with other species, but modifications in the cocoon web seem to be strongly determined by the characteristics and design of the spiders’ normal web. Keywords: cocoon construction, cocoon webs, ectoparasitoids, host parasitoid interaction Zusammenfassung. Wenig ist schon genug: das Kokonnetz von Kapogea cyrtophoroides (Araneae: Araneidae) induziert von Hy- menoepimecis heidyae (Ichneumonidae: Pimplinae). Das letzte Larvenstadium der koinobionten Ektoparasitoiden der Polysphincta Gattungsgruppe induziert bei ihren Wirten die Bildung eines Netzes, das die Puppe der Wespe während ihrer Entwicklung schützt. Es gibt die These, dass Änderungen in Struktur und Design des Kokonnetzes mit Lebensdauer und Charakteristika des normalen Netzes korrelieren. Kapogea cyrtophoroides (Araneidae) baut langlebige und kräftige normale Netze; dass das von Hymenoepimecis heidyae (Ichneumonidae) induzierte Kokonnetz fast identisch wie das normale Netz ist, unterstützt diese These. Die Larve spinnt ihren Kokon im dicht gewebten Zentrum desWirtsnetzes, verknüpft ihn mit dem Spinnennetz und führt dabei die für andereWespen der Gattungsgrup- pe bekannten Verhaltensmuster bei der Konstruktion durch. Das induzierte Verhalten der Spinne ist ebenso wie die Kokonkonstruktion sehr stereotyp und stimmt mit dem anderer Arten überein. Jedoch scheinen Modifikationen des Kokonnetzes stark von den Merkmalen und dem Design des normalen Spinnennetzes abhängig zu sein. Gilbert BARRANTES, Laura SEGURA-HERNÁNDEZ, Diego SOLANO-BRENES, Paul HANSON, Escuela de Biología, Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, 2060 San José, Costa Rica; E-mail: gilbert.barrantes@gmail.com , E-mail: laus1323@gmail.com, E-mail: diegosb04@gmail.com , E-mail: phanson91@gmail.com submitted 26.11.2017, accepted 16.2.2018, online 30.4.2018