Exposure of the African mound building termite, Macrotermes bellicosus workers to commercially formulated 2,4-D and atrazine caused high mortality and impaired locomotor response

Abstract

Recent empirical evidence suggests that herbicides have damaging effects on non-target organisms in both natural and semi-natural ecosystems. The African mound building termite, Macrotermes bellicosus, is an important beneficial insect that functions as an ecosystem engineer due to its role in the breakdown of dead and decaying materials. Here, we examined the effects of 2,4-D amine salt (2,4-D) and atrazine based herbicides viz. Vestamine ® and Ultrazine ® on the survival and locomotion response of M. bellicosus. Worker termites were treated with a range of concentrations of Vestamine ® (the recommended concentration: 6.25 ml per 500 ml of water, 0.25-and 0.5-fold below the recommended concentration and distilled water as control) and Ultrazine ® (the recommended concentration: 3.75 ml per 500 ml of water, 0.25-, 0.5-, 2.0-and 4-fold of the recommended concentration and distilled water as control) for 24 hours for the mortality test, and allowed to run for 15 seconds for the locomotion trial. All concentrations of both Vestamine ® and Ultrazine ® were highly toxic to worker termites and mortality increased as the concentration and time after treatment increased. For both herbicides, concentrations far less than the recommended rates caused 100% mortality. The speed of termites was significantly influenced by both Vestamine ® and Ultrazine ® as termites exposed to all tested concentrations of the herbicides exhibited reduced running speed than the control. These findings suggest that beneficial insects, especially M. bellicosus may experience high mortality (up to 100%) and reduced mobility if they are sprayed upon or come in contact with plant materials that have been freshly sprayed with (less or more than) the recommended concentrations of Vestamine ® and Ultrazine ®. The findings of our study calls for the reassessment of the usage of 2,4-D and atrazine based herbicides in weed control in termite and other beneficial insect populated habitats.

COMPARATIVE LETHAL IMPACT OF GLYPHOSATE AND PARAQUAT ON AFRICAN MOUND-BUILDING TERMITES (Macrotermes bellicosus Smeathman)

“…Also, reports of weed resistance to herbicides have resulted in the repeated application by farmers to eliminate weeds, consequently leading to harmful effects on non-target organisms (Duke, 2018). Despite the nutritional and ecological values of termites, there are limited studies on the adverse impact of herbicides on them (For exception, see Ejomah et al, 2020;Ekaye et al, 2022). Thus, in this study, we applied five concentrations of commercially manufactured glyphosate (Force up ® ) and paraquat (ParaQ ® ) on termites.…”

“…It has also been reported that, exposure to glyphosate disrupts the gut microbiota and decreased cognitive behaviours in Apis mellifera (Herbert, 2014;Motta et al, 2018). Furthermore, Ejomah et al (2020) revealed that atrazine and 2,4-D resulted in 100% mortality in M. bellicosus while paraquat-induced low fertility in Anisopteromalus calandrae (Lacoume et al, 2009). All these buttress the deleterious impactz of herbicides on non-target organisms.…”

“…The environmental fate of the active ingredients in the commonly used herbicides and the damage inflicted on different classes of non-target organisms have been reported (e.g. Aronzon et al, 2011;Abraham et al, 2018;Ejomah et al, 2020). In arthropods (e.g.…”

“…Also, there are many reports on the lethal effect of glyphosate and paraquat on various amphibians, reptiles and humans (Gill et al, 2018;Peillex and Pelletier, 2020). However, there are few reports on the effect of herbicides on the African mound termites (M. bellicosus) (Ejomah et al, 2020;Ekaye et al, 2022). Therefore, this study investigated the lethal effect of commonly used herbicides in Nigeria (glyphosate and paraquat) on M. bellicosus.…”

Survival of mushrooms and termites upon pesticide exposure in the cocoa agro-ecosystem

“…The mushroom exists in a symbiotic relationship with the termites, and this makes it difficult for domestication under laboratory conditions. Generally, termites are described as ecosystem engineers due to their activities in the soil which result in the availability of resources for other organisms [14]. However, they attack and destroy cocoa trees [15,16].…”