Gregarious behavior in desert locusts is evoked by touching their back legs

@article{Simpson2001GregariousBI,
  title={Gregarious behavior in desert locusts is evoked by touching their back legs},
  author={Stephen James Simpson and Emma Despland and Bernd F. H{\"a}gele and Tim Dodgson},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  year={2001},
  volume={98},
  pages={3895 - 3897}
}
Desert locusts in the solitarious phase were repeatedly touched on various body regions to identify the site of mechanosensory input that elicits the transition to gregarious phase behavior. The phase state of individual insects was measured after a 4-h period of localized mechanical stimulation, by using a behavioral assay based on multiple logistic regression analysis. A significant switch from solitarious to gregarious behavior occurred when the outer face of a hind femur had been stimulated… 

Figures from this paper

Mechanosensory-induced behavioural gregarization in the desert locust Schistocerca gregaria
TLDR
The data show for the first time that the gregarizing signal combines both exteroceptive and proprioceptive components, which travel in both nerves 5B1 and 5B2, and provides a powerful experimental method with which to elicit and study neuronal plasticity in this system.
Serotonin Mediates Behavioral Gregarization Underlying Swarm Formation in Desert Locusts
TLDR
It is shown that serotonin, an evolutionarily conserved mediator of neuronal plasticity, is responsible for this behavioral transformation, being both necessary if behavioral gregarization is to occur and sufficient to induce it.
Adult female desert locusts require contact chemicals and light for progeny gregarization
TLDR
The results suggest that a cuticular chemical factor at a specific developmental stage of conspecific locusts causes the solitarious females to produce large eggs that give rise to black hatchlings characteristic of gregarious forms (progeny gregarization), and that this or a similar compound occurs in other acridids, crickets and cockroaches but not in beetles.
A miniaturized assay to quantify effects of chemicals or physical stimuli upon locust activity
TLDR
It is demonstrated that there are inter‐ and intra‐phase dependent differences in activities of 5th instar nymphs after injections of the three different adipokinetic hormones.
Plasticity in the visual system is correlated with a change in lifestyle of solitarious and gregarious locusts.
TLDR
This work analyzed in both phases the responses of an identified visual interneuron, the descending contralateral movement detector (DCMD), which responds to approaching objects, and demonstrated that habituation of DCMD is fivefold stronger in solitarious locusts.
Pheromones in relation to aggregation and reproduction in desert locusts
TLDR
Recent progress, contradictory results and perspectives in desert locust pheromone research related to reproduction are summarized and discussed in this paper.
...
...

References

SHOWING 1-10 OF 21 REFERENCES
Spatial scales of desert locust gregarization.
TLDR
Computer simulations and a laboratory experiment are presented that show how differences in resource distributions, conspicuous only at small spatial scales, can have significant effects on phase change at the population level; local spatial concentration of resource induces gregarization.
Small‐scale processes in desert locust swarm formation: how vegetation patterns influence gregarization
TLDR
This model shows how population gregarization can result from simple processes operating at the individual level and demonstrates that small-scale vegetation distribution influences individual behavior and phase state and plays a role in population-level responses.
Analysis of phase-related changes in behaviour of desert locust nymphs
An assay is developed in which the behavioural responses of an individual locust to a group of conspecifics are used to derive an index representing the ‘behavioural phase status’ of that insect. The
Small‐scale vegetation patterns in the parental environment influence the phase state of hatchlings of the desert locust
TLDR
The offspring of locusts exposed to more clumped patterns of vegetation exhibited more gregarious behaviour when tested in a behavioural phase assay than did progeny from parents left in enclosures with more scattered vegetation.
The influence of environmental microstructure on the behavioural phase state and distribution of the desert locust Schistocerca gregaria
TLDR
It is shown that the fine‐scale distribution of food plants, perches and favourable microclimatic sites influences the spatial distribution of locusts, both in the laboratory and under semi‐field conditions.
Density–dependent aposematism in the desert locust
TLDR
It is demonstrated that density‐dependent nymphal colour change in the desert locust Schistocerca gregaria results in warning coloration (aposematism) when the population density increases and locusts consume native, toxic host plants.
...
...