Toxicity and Sublethal Effects of Autumn Crocus (Colchicum autumnale) Bulb Powder on Red Imported Fire Ants (Solenopsis invicta)

Abstract

Autumn crocus (Colchicum autumnale L.) is a medicinal plant as it contains high concentrations of colchicine. In this study, we reported that the ground powder of autumn crocus bulb is highly toxic to invasive Solenopsis invicta Buren, commonly referred to as red imported fire ants (RIFAs). Ants fed with sugar water containing 5000 mg/L of bulb powder showed 54.67% mortality in three days compared to 45.33% mortality when fed with sugar water containing 50 mg/L of colchicine. Additionally, the effects of short-term feeding with sugar water containing 1 mg/L of colchicine and 100 mg/L of autumn crocus bulb powder were evaluated for RIFAs’ colony weight, food consumption, and aggressiveness, i.e., aggregation, grasping ability, and walking speed. After 15 days of feeding, the cumulative colony weight loss reached 44.63% and 58.73% due to the sublethal concentrations of colchicine and autumn crocus bulb powder, respectively. The consumption of sugar water and mealworm (Tenebrio molitor L.) was substantially reduced. The aggregation rates decreased 48.67% and 34.67%, grasping rates were reduced to 38.67% and 16.67%, and walking speed decreased 1.13 cm/s and 0.67 cm/s as a result of the feeding of the two sublethal concentrations of colchicine and autumn crocus bulb powder, respectively. Our results for the first time show that powder derived from autumn crocus bulbs could potentially be a botanical pesticide for controlling RIFAs, and application of such a product could be ecologically benign due to its rapid biodegradation in the environment.

Fumigation Effects and Behavioral Responses of Red Imported Fire Ant (Solenopsis Invicta Buren) to Six Plant Essential Oils

“…At the moment, chemical insecticides are recognized as the most effective agents to control RIFA (Lin et al 2020). However, these chemicals can also cause a number of problems, including environmental pollution, pesticide residues, and an increase in production costs (Lin et al, 2020). There is an increasing relevance to botanical insecticides, especially since they usually have fewer adverse effects on humans and the environment than chemical insecticides.…”

“…Agricultural production, the environment, and human health are all seriously endangered by this species (Ascunce et al 2011). At the moment, chemical insecticides are recognized as the most effective agents to control RIFA (Lin et al 2020). However, these chemicals can also cause a number of problems, including environmental pollution, pesticide residues, and an increase in production costs (Lin et al, 2020).…”

Lethal effect of ethanol on Solenopsis invicta Buren and economic fish

“…Colchicine stem powder is a botanical pesticide used to control RIFA. The mortality of workers fed with 50 mg/L colchicine 24 h was 45.33% (Lin et al, 2020). However, its control effect in the field and toxicity in non‐target organisms, such as fish and other native species, are not known.…”

“…Chen and Oi (2020) indicated that the most promising alternative materials for prevention and controlling RIFA are natural compounds, of which only abamectin and spinosyn have been commercialized. Previous studies reported that baits containing ascorbic acid and autumn crocus stem powder have highly toxic effects on the RIFA (Lin et al, 2020; Ning et al, 2020). The sweeteners erythritol and saccharin also have lethal effects on the RIFA at relatively low concentrations (Zhang et al, 2017).…”

“…Previous studies reported that baits containing ascorbic acid and autumn crocus stem powder have highly toxic effects on the RIFA (Lin et al, 2020;Ning et al, 2020). The sweeteners erythritol and saccharin also have lethal effects on the RIFA at relatively low concentrations (Zhang et al, 2017).…”