Hymenoepimecis castilloi Pádua & Sääksjärvi, 2020

Velasco-Cárdenas, Andrés F., Jesús, Velasco-Cárdenas ·, Jacome-García, C., Pádua, Diego G. & Kloss, Thiago G., 2024, Behavioral Modification of Leucauge mariana Induced by an Ichneumonid Spider-Parasitoid, Hymenoepimecis castilloi, in the Colombian Andes, Neotropical Entomology 53 (2), pp. 364-371 : 365-367

Hymenoepimecis castilloi Pádua & Sääksjärvi, 2020 ( Fig. 2a, b ).

Diagnosis. See Pádua et al. (2020).

Male. ( Fig. 2b ). Similar to female in structure and coloration, with body 9.0– 10.6 mm; face approx. 0.6 times as width as high; posterior ocelli separated from eyes by 0.7–0.8 times its own maximum diameter; fore wing 6.3–7.7 mm; tarsal claw simple; metasoma slender, tergite I

1.4–1.7 times as long as posteriorly width; tergite II 1.25–1.5 times as long as posteriorly width; hypopygium with posterior margin weakly concave.

Material examined. COLOMBIA, Cundinamarca, Pacho (5.203806N, − 74.108889W) [= 5°12′13.7″N, 74°06′32.0″W], 2583 mASL, collection of parasitized Leucauge sp. [= L. mariana ], 23.III.2022 (A. Velasco and J. Jacome leg.), 6♂♂ and 6♀♀, INPA ; Valle [= Valle del Cauca], Arriba Villa Carmelo , 31.VIII.1975 (L. Stange leg.), 1♀, FSCA .

Distribution. Argentina; Colombia (new record); Peru.

Web modification

Typical prey capture webs of non-parasitized spiders had 21.3 ± 9.8 (mean ± S.D.) spirals and 23.6 ± 4.04 radii (N = 3, Fig. 3a ). Webs of parasitized spiders by second instar wasp larvae had 17.2 ± 8.9 (mean ± S.D.) spirals and 18.5 ± 3.4 radii (N = 7, Fig. 3b ). All webs of non-parasitized and parasitized spiders by second instar wasp larvae did not present tangle threads below the hub (N = 11) ( Fig. 3a, c ). Also, all webs of non-parasitized spiders and seven webs of parasitized spiders by second instar wasp larvae presented radial lines that converged to a hub with an open hole in the center ( Fig. 3a, b ). Only one web of parasitized spiders by second instar wasp larvae did not present an open hole in the hub and spirals; however, this web had radial lines that converged to a hub ( Fig. 3c ). Also, we observed that non-parasitized and parasitized spiders by second instar wasp larvae presented 1–3 circular hub lines ( Fig. 3a–c ).

We observed that all cocoon webs (N = 7) of parasitized spiders lacked adhesive spirals, an open hole in the center and hub spiral ( Fig. 4a–e). Five cocoon webs were built in web aggregates of spiders, with non-parasitized and parasitized individuals. In these aggregations, all parasitoid cocoons were suspended in a vertical line constructed by the 3rd instar larvae. This line is easily distinguishable due to its orange coloration and thicker texture compared to the normal lines of the spider’s web. The wasp would remain hanging at the exact location where the spider died, and it was common for the spider to die on one of the lines that comprised its own web or one of the sharing frame lines (vertical or horizontal) of other spiders within the aggregation ( Fig. 4a, b). Nevertheless, it was not possible to determine which was the original web of these individuals in aggregates because the parasitized spiders in the aggregate moved through the sharing lines to other webs from the aggregate constantly. The place of death of the spiders did not have a pattern of modified web (the webs did not present radial lines that converged to a hub) ( Fig. 4a, b). However, two of the five parasitoid cocoons in these aggregates were hanging on a vertical line from an irregular and dense web with a sparse tangle below the hub seemingly constructed by the parasitized spiders. These two webs also did not have reinforced radii converging to a hub ( Fig. 4c, d). Finally, we observed two parasitized individuals that built their cocoon webs in the vegetation, away from the aggregates of individuals. These cocoon webs had three and four reinforced radii, which converged to a hub and where the parasitoid hung their cocoon in a vertical line ( Fig. 4e). All cocoon webs, if present, had lines connected to vegetation at multiple points ( Fig. 4c–e), which was not observed in webs of non-parasitized spiders ( Fig. 3a ).

Figures

Fig. 2 Hymenoepimecis castilloi Pádua and Sääksjärvi, 2020: a Habitus (♀); b Habitus (♂)

Fig. 3 a Web of unparasitized individuals of Leucauge mari- ana, absence of tangle threads below the hub. b Web of an individual of Leucauge mariana parasitized by an Hyme- noepimecis castilloi second instar larvae. c Modified web of parasitized individuals of Leucauge mariana by a second instar larvae of Hymenoepime- cis castilloi, without open hole in the hub and spirals. d Adult of Leucauge mariana being killed by a third instar larvae of Hymenoepimecis castilloi, dorsal tubercles can be seen in the larvae