Saturday, January 5, 2019

[Entomology • 2018] First Record of Epipompilus excelsus (Hymenoptera, Pompilidae) As A Koinobiont Ectoparasitoid of Ariadna mollis (Araneae, Segestriidae)

  Adult female of Ariadna mollis (Holmberg, 1876) (Segestriidae) 
parasitized by Epipompilus excelsus (Bradley, 1944) (Pompilidae).

in Villanueva-Bonilla, Brescovit, Santos & Vasconcellos-Neto, 2018. 

Epipompilus Kohl comprises 52 species of wasps that are parasitoids of spiders; 16 species occur in the Neotropical region and 36 species occur in the Australian region. The biological knowledge of this genus is limited and its interactions and host spiders are still incipient. Here, we report some behavioural and biological characteristics of E. excelsus, a parasitoid of the tube-dwelling spider Ariadna mollis. We observed an E. excelsus female attacking an adult female of A. mollis in São Paulo, Brazil. We photographed daily the larval development of the wasp, from the egg stage to adult emergence. The entire developmental cycle of the wasp took 24 days. This period was shorter than the developmental periods of wasps belonging to other genera of Pompilidae. Although all species within Pompilidae use spiders as host, they present great behavioural diversity, characterized by different ethological sequences. In conclusion, this study demonstrated that the Neotropical species of Epipompilus exhibit biological characteristics similar to the Australian species, acting as a koinobiont ectoparasitoid, but displays differences in larval morphology. Studies on other species could elucidate the extent of these differences and similarities, contributing to our understanding of the evolutionary history of Epipompilus, and consequently of Pompilidae.

Keywords: Egg-wasp development, Neotropical, Parasitoid, Tube-dwelling spider

Figure 1. Adult female of Ariadna mollis (Segestriidae) parasitized by Epipompilus excelsus (Pompilidae).
A) Wasp on the back of the spider (the arrow indicates the position of the egg in the abdomen). B) A. mollis moving slowly minutes after being paralyzed. C) Larval I instar of the wasp adhered to the abdomen of the spider.
D) Larval II instar. E) Larval III instar. F) Larval IV instar feeding from the abdomen of the spider.
G) Larva eating the remains of the legs and abdomen of the spider. H) The cocoon containing the meconium (red arrow). I) Adult female of E. excelsus.

 German Antonio Villanueva-Bonilla, Antonio Domingos Brescovit, Eduardo dos Santos and João Vasconcellos-Neto. 2018. First Record of Epipompilus excelsus (Bradley, 1944) (Hymenoptera, Pompilidae) As A Koinobiont Ectoparasitoid of Ariadna mollis (Holmberg, 1876) (Araneae, Segestriidae). Journal of Hymenoptera Research. 66: 15-21.  DOI:  10.3897/jhr.66.28915