Proof of concept for eliminating Aedes aegypti production by means of integrated control including turtles, copepods, tilapia, larvicides, and community participation in Monte Verde, Honduras

The invasive twospot livebearer's biology, and its current and potential global distribution

Poeciliids are widely recognized as successful invaders, possessing traits associated with invasion success. Native to Central America and south-eastern Mexico, the twospot livebearer (Pseudoxiphophorus bimaculatus) is a species recently recognized as invasive in both Central and northern Mexico. Despite its invasive status, limited research exists on its invasion process and the potential threats it poses to native species. In this study, we conducted a comprehensive review of the current knowledge on the twospot livebearer and mapped its current and potential distribution worldwide. The twospot livebearer shares similar traits with other successful invaders within the same family. Notably, it exhibits high fecundity throughout the year and demonstrates resilience to highly polluted and oxygen-deprived water conditions. This fish serves as a host for several parasites, including generalists, and has been extensively translocated for commercial purposes. Recently, it has also been used for biocontrol within its native range. Apart from existing outside its native range, the twospot livebearer, under current climate conditions and if transported there, could readily colonize biodiversity hotspots in tropical zones worldwide, including the Caribbean Islands, the Horn of Africa, North of Madagascar Island, south-eastern Brazil, and others located in southern and eastern Asia. Given that this fish is highly plastic and our Species Distribution Model, we consider that all areas with a habitat suitability >0.2 should prevent its arrival and establishment. Our findings underscore the urgent need to recognize this species as a threat to freshwater native topminnows and prevent its introduction and spread.

How can the copepod Mesocyclops longisetus (Thiébaud, 1912) be used to control mosquito production effectively in pots, plates, and slabs?

We tested the effectiveness of predation by the cyclopoid copepod Mesocyclops longisetus (Thiébaud, 1912) in Culicidae and Chironomidae larvae, aiming to test if (i) the introduction of copepods effectively controls mosquito larvae and (ii) the density of copepods is important for ensuring control. We conducted two semi-field experiments: the first involved 14 experimental runs over 75 consecutive days, compared in a randomized block design, four repetitions per treatment in each experimental run (block); and the second experiment involved a total of five experimental runs, lasting 25 and 33 days each. In the first experiment, culicid larvae were preyed on by copepods, especially at high copepod densities (15 copepods per litre), which reduced culicid densities by approximately 61% and 64% for different containers, considering that the environmental temperature declined linearly by about 10ºC from February (summer) to May (autumn) (32ºC to 22ºC). Even the lowest copepod density (5 per liter) produced a substantial reduction in the abundance of culicid larvae when chironomid larvae were abundant. On the other hand, there was no effective control of chironomid larvae. In the second experiment, increases in Culicidae and Chironomidae were concomitant with decreases in copepods. Thus, when the copepods were in high densities, there was no increase in insects, although the larvae of culicids were not eliminated from the experimental units. We conclude that the introduction of copepods in small containers and ponds can be useful for the control of culicid larvae without harming chironomid populations, and densities up to 15 per litre are recommended, although even low densities cause substantial reduction.