Vanishing aquatic insects, amphibians abetting disease outbreaks
Source: Chronicle News Service / Ngangom Suraj
Imphal, January 12 2024:
With every available vegetation, especially in urban areas, turning into concrete and water bodies including rivers and wetlands filled up for human settlements or left polluted, many species of edible aquatic insects and amphibians have disappeared unnoticed.
Though the effect of their disappearances may not seem apparent, it is quite alarming as it abets outbreak of vector borne diseases.
The Kongba River also faces similar fate by virtue of flowing through some of the densely populated regions of Imphal city, especially in Imphal East district.
The river has become one of the most polluted rivers in the state and over the years it has become nothing but breeding grounds for mosquitoes which are carriers of several vector-borne diseases.
Owing to scanty rainfall and high pollution level, many species of once abundant aquatic edible insects and amphibians which feed on the larvae of mosquitoes and disease-causing germs, have completely disappeared.
In an exclusive interview with this daily, Indian Council of Agricultural Research Complex for NEH Region, Manipur Centre senior scientist Dr Ningombam Arati pointed out that disappearance of several species of aquatic edible insects and amphibians have aggravated vector-borne disease outbreaks such as malaria and dengue in the state.
She pointed out that when quality of water decreases with contamination, larvae or eggs of aquatic insects and amphibians which feed on larvae of mosquitoes and other germs, cannot survive.
"Mosquitoes are natural exterminators; they are designed to spread diseases and kill people or animals so as to prevent population explosion.
Even so, nature also, keep in check to maintain its population in the form of aquatic insects and amphibians which feed on their larvae.
When such useful species disappears due to pollution and exploitation of the ecosystem, the population of mosquitoes and other vector-borne disease-causing species increase rapidly thereby aiding disease outbreaks," Dr Arati explained.
Citing an instance on how aquatic insects help in controlling the population of mosquitoes, Dr Arati said that larvae stage of dragonflies known as nymph feed on the larvae of mosquitoes in water while adult dragonflies feed on adult mosquitoes.
Stressing the need to conserve the useful species, Dr Arati also pointed out that humans have never succeeded, till date, in controlling the population of vector-borne disease carriers even by using Dichlorodiphenyltrichloroethane or DDT, which is known to cause adverse environmental effects, such as those to wildlife, as well as its potential human health risks, since the time of second world war.
About 39 species of insects belonging to 25 genera and 19 families including Acisoma panorpoides (Charang, Maikhumbi), Geris lacustris (Longkhajing), Hydrometa greeni (Eshing mi), Hydrous ol-ivaceus (Tharaikopi), Laccotrephes maculatus (Haonaosek), Lethocerus inducus (Naosek), Valanga nigricornis (Koujieng), etc., were used as food, Dr Arati stated, adding that as many as 39 insect species belonging to 39 genera and 28 families are also used in preparation of ethno-therapeutic.
The insects used for traditional medicinal purposes are either consumed raw, roasted or cooked, or made into ointment or paste form to be applied to the affected areas, she added.
Emphasising the need to protect and conserve rivers, Dr Arati reminded that every life form requires water for survival, which the humans often forget and are also the culprits for causing harms to rivers and other water bodies.
Because of carelessness and selfish human nature who only thinks of profit or benefits, all other lifeforms are suffering, she lamented, while pointing out that it is also only the humans who can rejuvenate affected water bodies to their once majestic forms.
Noting that all edible insects are collected from the wild and there is no conservation effort at present, Dr Arati urged parties or authorities concerned to help farmers identify which type of insects are useful and which are not.
Farmers often mistake cluster of eggs of such useful insects as harmful and spray pesticide or insecticide, she said, while urging the farmers to collect such clusters of eggs if they happen to spot in their held and to release them in safe waters.
Dr Arati also opined that reforestation programmes through large scale plantation of rare indigenous fruit trees or bamboo with community participation, in the over exploited hill ranges of the state for poppy cultivation, will not only help retain water in the catchment areas or the river head but will also provide sustainable livelihood to the locals.
It will further help in maintaining the flow and quality of water of rivers thereby also facilitating a comeback chance for many aquatic insects, amphibians and fish species, she reiterated.
(The report is filed under the 4th Media Fellowship Programme on Climate Change Reporting under the sponsorship of Directorate of Environment and Climate Change, government of Manipur) .