15.10.2022

LOVE BITES in Spiders - Some new insights!

In some of his publications and lectures, Dr. Peter Jaeger from Senckenberg Museum (Frankfurt) has already reported several times on so-called "love bites" in spiders. These are apparently small, more or less round scars on the prosoma and sometimes also on the legs (Pic 1, green arrow) of some adult females of araneomorph spiders, for example from the families Philodromidae and Sparassidae, presumably caused by the males during mating. Jaeger writes "It is assumed that the male grabs the female during the copulatory process with his fangs to have a better grip orsubdue the female a longer time." (Jaeger 2021). In Thanatus fabricii, the research group led by Lenka Sentenská and Stano Pekar of Masaryk University found that their males bite females on the legs prior to mating intent. The females are paralyzed by this bite and the poison effect revealed in such a way that the males can perform the mating act without problems and danger (Sentenská et al. 2020).

Since Volker von Wirth is in the lucky position to observe a population of Thanatus vulgaris (Pic 2) living on the walls in the breeding rooms of the Austrian food insect breeding of Kreuch und Fleuch (Pic 3, green arrows). He had the idea to capture a few males and females of this species and to observe and document their interesting behavior towards each other in the context of mating and to see if the so-called "love bites" would also occur in this species in advance of the mating. He succeeded in documenting the "love bites" behavior observed by Jaeger and Sentenská et al. for this Thanatus species as well, as the attached movie and picture shows (Video 1 & Pic 4).

Very noticeable is the haemolymphae drop, which can be seen in the video immediately after the bite at the bitten site. The closing of this wound with chitin then leads to the scars mentioned by Peter Jaeger and Lenka Sentenska and shown in Pic 1.

During another mating attempt with another pair he could also detect a bite of the male (Video 2, beginning of the Video), but no haemolymphae can be seen emerging afterwards. During the mating the female also behaved very calm and seemed paralyzed. Whether this is a consequence of the bite or a normal female reaction during mating remains unanswered for now.

Literature:

Jaeger, Peter. (2021). Enigmatic “love bites” and an indirect mating plug: revision of Thunberga Jäger, 2020 with description of new species (Araneae: Sparassidae: Heteropodinae). Arachnology. 18, (7), 718–765

Lenka Sentenská, Ondrej Šedo, Stano Pekár (2020): Biting and binding: an exclusive coercive mating strategy of males in a philodromid spider, Animal Behaviour, Volume 168, 59-68