Fewer mosquitoes and cockroaches spotted this summer may come as welcome news to the public but it is a clear sign of ‘ecological disaster’, according to experts.
As temperatures soar and people struggle to cope with the heat, many have observed that the summer pests have not appeared as often as usual.
The most dramatic decrease seen
Pest control consultant Arnold Sciberras spoke of an estimated 30 per cent drop in these two groups in comparison to past years, explaining it was the most dramatic decrease he had seen.
“Changes in populations appear every year, I remember it happened once in 1998 and in 2012 but not as severe as this year,” he said.
While no official studies made, Sciberras explained he was constantly gathering information from his clients and conducting research.
A lack of water was the main factor behind the dwindling numbers, he reckoned.
Mosquitoes need water to thrive and breed and cockroaches will remain in the sewers and other humid areas if the conditions are too dry.
The drop was particularly alarming since mosquitoes and cockroaches were biological indicators of the health of a habitat, he pointed out.
When they decline a whole food chain collapses
Annual precipitation levels have been falling, with only two out of the last six years reaching normal targets while the remaining four recorded under 70 per cent of the normal rainfall.
“Although it may seem good for the public that these pests are in decline, in fact, it is a sign of ecological disaster,” he said.
“If such hardy pest species cannot survive, one could just imagine the effect these climate conditions are having on the beneficial, rare, endangered indigenous or endemic species,” he pointed out.
As a naturalist, Sciberras had observed the most visibly hit species by the change in climate conditions was the butterfly.
The dwindling numbers of mosquitoes and cockroaches also had consequences higher up the food chain, he added.
“Although people hate these pests, when they decline, usually, predators of these species decline as well and a whole food chain collapses,” he said.
Biologist Alan Deidun also weighed in on the severity of the situation explaining that mammals, such as bats and hedgehogs as well as 10 species of reptiles, including chameleons and geckos, depended on these insects and others as fodder.
Devastating effects
He pointed out that disturbances so low in the food chain could have devastating effects.
“An ecosystem can survive without the higher levels. It suffers when the species on the lower levels are impacted. The food pyramid starts to wobble since its foundation is being affected,” he noted.
The low amount of rain recorded over the last few years, as well as the extreme heat and lack of humidity this year had led to drier conditions, putting immense strain on the ecosystem and stressing even the hardiest native trees, Deidun said.