The effects of insecticide-contaminated prey on predatory behavior in the scorpion Tityus pusillus

 

Pesticides are commonly used in the fight against "pest-insects" like cockroaches. This can be harmful for other animals, like the predators eating these pesticide-contaminated prey and nature in general. Thayna Rhayane de Brito-Almeida and co-workers have recently published an article investigating the effects of insecticide-contaminated prey on predatory behavior in the scorpion Tityus pusillus  Pocock, 1893 (Buthidae).

The study shows that the acceptance rate prey exposed to insecticides was the same as for prey in the control group. However, there were some modifications in the prey capture behavior in the insecticide group compared to the control group. Also, scorpions that had ingested prey exposed to one type of insecticides showed signs of intoxication, but these were very short lived. It seems that Tityus pusillus is resistant to the insecticides tested.

Abstract:
In many countries, insecticide application in cities is the primary method used for urban pest control. However, the indiscriminate use of these chemical compounds may prejudice native predators which consume contaminated prey. This research aimed to evaluate the behavioural response of Tityus pusillus scorpions to prey previously exposed to different groups of insecticides. Two chemical compounds were tested: pyrethroid cypermethrin spray and the bait-type insecticide indoxacarb, which is an oxadiazine compound. Sixty scorpions were divided into three groups of 20 specimens each: a control group fed on cockroaches not exposed to any insecticide, a pyrethroid group fed on cockroaches previously exposed to cypermethrin, and an indoxacarb group fed on cockroaches exposed to oxadiazine. No difference was detected in prey acceptance among the three groups. Scorpions exposed to oxadiazine showed a non-significant trend toward longer capture latency, while pyrethroid-exposed individuals displayed transient signs of intoxication, with most recovering. Despite these short-term behavioural alterations, scorpions accepted contaminated prey, with no treatment effect on capture latency or acceptance probability. Our findings indicate short-term tolerance to the tested insecticides.

Reference:
Brito-Almeida T, Barbosa de Moura GJ, Lira A. Insecticide-contaminated prey alters predatory behaviour in the scorpion Tityus pusillus (Scorpiones: Buthidae). Arachnology. 2026;20:576–80. [Subscription required for full text]