I’ve spoken quite about about tarantula “personalities” and temperaments over the past few years. The consensus is that tarantulas don’t actually have the brainpower or ability to have personalities, however they may be more predisposed to more calm or defensive temperaments or moods.

According to research, a more aggressive tarantula personalty has been linked to instances of tarantula cannibalism during the mating process. Many of us have accepted possible cannibalism during the mating process as a simple fact of life, but new research sheds some light on why this happens.

Thanks to a new investigation by the Experimental Station of Arid Zones (EEZA-CSIC), we now have some insight into why a female tarantula may be inspired to eat her mate after copulation. Rubén Rabaneda-Bueno, first author of the study on tarantulas published in Ethology, explained:

“This tendency towards cannibalism could depend on the aggressive genetics of the females which make them attack males in the same way as they attack prey.”

In evaluating the personalities of female tarantulas for sexual cannibalism, randomly selected tarantula males were introduced to a group of female virgin tarantulas and the authors of the study documented whether they attacked the males or allowed the mating process to happen nicely.

Before these introductions between the spiders, researchers studied the personality of the female tarantulas when they were eating and noted that some were much more ravenous. Researchers were basically looking for a connection between the female tarantulas’ personality, whether more canibalistic or more docile, and where there was correlation to cannibalism in the mating process. Rabaneda-Bueno said:

“More cannibalistic females were also more voracious towards their prey, and thus the better nourished. This is surprising since they have more nutritive resources to invest in their offspring before finding the first males. Their priority should be ensuring the sperm’s fertilisation of their eggs instead of eliminating their potential donors.”

“We reached the conclusion that there are aggressive genetics which vary among females and make them act aggressively both when they feed off prey and when they approach a male in courting,” added Jordi Moya Laraño, director of the study. “Others are docile in both contexts, highlighting the existence of different personalities.”

So it seems that this study found that female tarantulas with a more aggressive personality who tend to be more ravenous eaters, not only fatten up more but are more likely to eat their mates when they are virgins. As for the more docile virgin female tarantulas, they tended to consume less prey and were more likely to copulate before even thinking about eating their partners. Rabaneda pointed out:

“While docile females attack inferior males and prefer to mate with superior males, aggressive females kill males regardless of their condition, which demonstrates their inability to distinguish males as sources of sperm or food, indiscriminately cannibalizing them.”

As there was a correlation between levels of female aggression in tarantulas to the likelihood of attacks on male taratnaulas during mating, I wonder if this might help tarnatula breeders assess their risk better. To read more of this study, go here!