Effect ofParanosema locustae(Microsporidia) on the behavioural phases ofLocusta migratoria(Orthoptera: Acrididae) in the laboratory

Abstract

The ability of parasites to modify the behaviour of their hosts is a wide spread phenomenon, but the effects of microsporidian parasites on locust behaviour remain unexplored. Here the frequencies of directional changes (ND) and jumping (NJ) per minute of gregarious locusts infected with 2000 spores of the microsporidian parasite Paranosema locustae were significantly different from those of untreated locusts 10 and 16 days after infection, being similar to values for solitary nymphs. In contrast, the behaviour of locusts inoculated with the lower doses of 200 spores/locust was sometimes like that of solitary nymphs. At other times, behaviour was intermediate between solitary and gregarious, i.e. transitional. The rearing density did not affect the turning and jumping behaviour of infected locusts, and their behaviours were similar to those of solitary locusts at 10-16 days after infection. Our study demonstrates that infection with P. locustae may lead gregarious locusts to change some of their behaviour to that typical of solitary locusts.

Increase of Albinistic Hosts Caused by Gut Parasites Promotes Self-Transmission

“…It is well known that variations in locust body color are related to their density ( Maeno and Tanaka, 2008 ). Some articles have reports of ambient temperature and background colors leading to variations in insect body color ( Goulson, 1994 ; Valverde and Schielzeth, 2015 ), and some studies have demonstrated that P. locustae infection observably affected both behavior and morphological phase transformation ( Fu et al, 2010 ; Feng et al, 2015 ). But mechanisms by which pathogens change host colors have rarely been reported.…”

Influences of Microbial Symbionts on Chemoreception of Their Insect Hosts

“…Healthy locusts exposed to olfactory stimuli from parasite-infected conspecifics exhibit a significant reduction in serotonin levels, leading to decreased gre-gariousness [71]. This transformation is not conducive to the spread of parasites but is conducive to the survival and development of locust populations [72]. Infection with the fungal pathogen Erynia neoaphidis decreases the sensitivity of the pea aphid Acyrthosiphon pisum to alarm pheromone, and the percentage of nonresponding aphids increases as the disease progresses [73].…”