Tritrophic interactions between a fungal pathogen, a spider predator, and the blacklegged tick

Perspectives of vector management in the control and elimination of vector-borne zoonoses

The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004.

Predation of ant species Lasius alienus on tick eggs: impacts of egg wax coating and tick species

Several animal species, including ants, have been reported to be capable of predation on ticks. However, determining factors in most interactions between ticks and predators have not yet been fully deciphered. We hypothesized that the ant species Lasius alienus, which is unknown whether it has any impact on ticks, may exhibit predation on the eggs of tick species Hyalomma marginatum, H. excavatum, and Rhipicephalus bursa, and that the tick egg wax can be the main determinant in possible predation. In the study, 6300 tick eggs with the natural wax coating (waxed/untreated) and 2700 dewaxed tick eggs, the wax of which was removed in the laboratory, were repeatedly presented to the foraging workers belonging to three different ant nests in their natural habitat. Depending on the tick species and trials, the rate of the eggs carried by the ants ranged from 12.8 to 52.1% in the waxed and from 59.8 to 78.4% in the dewaxed eggs. It was observed that the dewaxing process both increased the interest of the ants in the eggs and resulted in a reduction in the variation associated with tick species. This study showed that L. alienus has a predatory effect on tick eggs, the severity of this impact is closely associated with the tick species, the tick-associated difference is caused by the species-specific property of the egg wax, and the variety in the protective effects of the wax seems to be an evolutional result of the biological and ecological adaptation process of the species.

The ecology of zoonotic parasites in the Carnivora

The order Carnivora includes over 300 species that vary many orders of magnitude in size and inhabit all major biomes, from tropical rainforests to polar seas. The high diversity of carnivore parasites represents a source of potential emerging diseases of humans. Zoonotic risk from this group may be driven in part by exceptionally high functional diversity of host species in behavioral, physiological, and ecological traits. We review global macroecological patterns of zoonotic parasites within carnivores, and explore the traits of species that serve as hosts of zoonotic parasites. We synthesize theoretical and empirical research and suggest future work on the roles of carnivores as biotic multipliers, regulators, and sentinels of zoonotic disease as timely research frontiers.

Bugs scaring bugs: enemy-risk effects in biological control systems

Enemy-risk effects, often referred to as non-consumptive effects (NCEs), are an important feature of predator-prey ecology, but their significance has had little impact on the conceptual underpinning or practice of biological control. We provide an overview of enemy-risk effects in predator-prey interactions, discuss ways in which risk effects may impact biocontrol programs and suggest avenues for further integration of natural enemy ecology and integrated pest management. Enemy-risk effects can have important influences on different stages of biological control programs, including natural enemy selection, efficacy testing and quantification of non-target impacts. Enemy-risk effects can also shape the interactions of biological control with other pest management practices. Biocontrol systems also provide community ecologists with some of the richest examples of behaviourally mediated trophic cascades and demonstrations of how enemy-risk effects play out among species with no shared evolutionary history, important topics for invasion biology and conservation. We conclude that the longstanding use of ecological theory by biocontrol practitioners should be expanded to incorporate enemy-risk effects, and that community ecologists will find many opportunities to study enemy-risk effects in biocontrol settings.

Red imported fire ant (Solenopsis invicta) aggression influences the behavior of three hard tick species

Few studies have documented the indirect effects of predators on tick behavior. We conducted behavioral assays in the laboratory to quantify the effects of a highly abundant predator, the red imported fire ant (Solenopsis invicta), on three species of ticks endemic to the southern USA: the lone star tick (Amblyomma americanum), the Gulf Coast tick (A. maculatum), and the Cayenne tick (A. mixtum). We documented ant aggression toward ticks (biting, carrying, and stinging) and determined the effects of ants on tick activity. Ticks were significantly less active in the presence of fire ants, and tick activity was negatively associated with ant aggression, but in many cases the effects of fire ants on ticks varied by tick species, stage, and engorgement status. For example, fire ants took half as long (~ 62 s) to become aggressive toward unfed A. americanum adults compared with unfed A. maculatum, and only ~ 8 s to become aggressive toward engorged A. maculatum nymphs. Correspondingly, the activity of unfed A. americanum adults and engorged A. maculatum nymphs was reduced by 67 and 93%, respectively, in the presence of fire ants. This reduction in tick activity translated to less questing by unfed ticks and less time spent walking by engorged nymphs. Our results suggest that fire ants may have important non-consumptive effects on ticks and demonstrate the importance of measuring the indirect effects of predators on tick behavior.