Data from: Maternal care thwarts parasitoids in the invasive brown widow spider (Latrodectus geometricus)

Maternal care can maximize offspring survival and may contribute to the
establishment success of invasive species. The brown widow spider,
Latrodectus geometricus, is a successful invader worldwide. Here, we
investigated the role of maternal care in enhancing its success. We
compared the defence mechanisms of the invasive L. geometricus with those
of another widow spider native to the Negev desert, L. pallidus, against
an egg sac parasitoid wasp. Both spider species exhibited guarding
behaviours following exposure to wasps; however, only L. geometricus
efficiently evaded and successfully killed the parasitoid. Accordingly,
its egg sacs were parasitized less frequently than those of L. pallidus.
Next, we evaluated the defensive role of the silk spike-like structures on
L. geometricus egg sacs. When spikes were removed from half of the egg sac
surface, the wasps laid more eggs on the spike-free side. In an additional
experiment, L. geometricus females increased spike density on subsequent
egg sacs after exposure to the parasitoid. We showed that L. geometricus
employs both behavioural defences and modifications to the egg sac
structure to protect against the parasitoid. These defences may provide L.
geometricus an advantage over native species in its invasive range,
potentially contributing to its invasion success.