Madagascar – Looking for locusts

Madagascar – Looking for locusts

13/11/2014

The sun is almost at its zenith, the ground bristling with termite mounds, the vegetation sparse with rice fields dotted within the low-lying areas. The survey team has scanned the ground and the skies in vain – not a single locust to be seen, even though this is a region where they might be expected.

First locusts spotted / premiers criquets repérés

The helicopter lands and the three-strong team gets out, setting off in different directions to survey the area on foot. The aim is to determine whether locusts are present, and if so, to characterize them. 

The scout walks with a purposeful stride, assessing the soil moisture and on the lookout for the slightest movement. Sometimes it is only a bird, a lizard or a snake, and sometimes it is a locust. The scout slows down and tries to get closer to it. The first thing to do is to identify the species. Only two species retain his attention: the Migratory Locust (Locusta) and the Red Locust (Nomadacris), as these are the only two species that can behave gregariously, forming hopper bands and adult swarms. When locusts behave in this way, they become a plague.   

The scout counts the number of individuals he observes per square metre or hectare, and captures some locusts. The captured locusts will enable him to determine the phase (pigmentation, behaviour and morphology criteria) and the stage of the locusts’ development (young, able to breed –i.e. mature adults, those that have already laid eggs or old). This information is crucial to establish priorities for future anti-locust operations. 

During the walk, it is not unusual to come across someone tending their herd of zebus, or a villager with a bucket full of termites to feed their turkeys. These encounters enable the scout to explain the presence of the helicopter and the activities he is carrying out, and to gather information about the latest presences of locusts.