Linseed Oil Affects Aggregation Behaviour in the Desert Locust Schistocerca gregaria—A Potential Swarm Disruptive Agent

Abstract

Gregarious desert locusts constitute very destructive agricultural pests. They aggregate and form collectively moving swarms that devastate vegetation and reduce crop production. To combat gregarious locusts, a bio-pesticide formulation that contains linseed oil as the main component was described recently. Since linseed oil is rich in fatty acids, some of which function as necromones that indicate injury or death in various insect species, we investigated the influence of linseed oil on the aggregation behaviour of sexually mature gregarious desert locusts. For this reason, we performed a series of aggregation experiments with six individuals of the same sex and brushed the wings of one individual (target individual) with linseed oil. The time the oil brushed target males spent close to any other individual was reduced in 76% of trials (average reduction of 18%), whereas the time target females spent in groups with members of the same sex did not alter. These results suggest that linseed oil may act as a bioactive agent that has the potential to disrupt swarm formation.

High fitness areas drive the aggregation of the sea urchin Mesocentrotus nudus

“…However, the present study indicates that the protective function is probably a consequence, rather than a cause. Consistently, functions (for example, producing phenylacetonitrile against predators) occur after the aggregation of the locust Locusta migratoria migratorioides ( Torto et al, 1994 ; Abdelatti & Hartbauer, 2020 ). In addition, the present results well explain the finding of Bernstein, Schroeter & Mann (1983) that predators induce the hiding of sea urchin at low density while the aggregation at high density.…”