Rearing and Long-Term Maintenance of <em>Eristalis tenax</em> Hoverflies for Research Studies

Abstract

With an estimated 6000 species worldwide, hoverflies are ecologically important as alternative pollinators to domesticated honeybees. However, they are also a useful scientific model to study motion vision and flight dynamics in a controlled laboratory setting. As the larvae develop in organically polluted water, they are useful models for investigating investment in microbial immunity. While large scale commercial breeding for agriculture already occurs, there are no standardized protocols for maintaining captive populations for scientific studies. This is important as commercial captive breeding programs focusing on mass output during peak pollination periods may fail to provide a population that is consistent, stable and robust throughout the year, as is often needed for other research purposes. Therefore, a method to establish, maintain and refresh a captive research population is required. Here, we describe the utilization of an artificial hibernation cycle, in addition to the nutritional and housing requirements, for long term maintenance of Eristalis tenax. Using these methods, we have significantly increased the health and longevity of captive populations of E. tenax compared to previous reports. We furthermore discuss small scale rearing methods and options for optimizing yields and manipulating population demographics.

The potential management of the drone fly (<i>Eristalis tenax</i>) as a crop pollinator in New Zealand

“…Eristalis tenax normally has multiple generations per year (Dziock 2006). In the laboratory, females were found to produce around 3000 eggs over a 2-month period and their lifespan without hibernation was approximately 3 months at around 21.5 o C (Nicholas et al 2018). This result contrasts with earlier findings by Jarlan et al (1997b), who found females survived under greenhouse conditions for 2-4 weeks, and males rarely beyond 3 weeks (temperature uncontrolled).…”

“…This result contrasts with earlier findings by Jarlan et al (1997b), who found females survived under greenhouse conditions for 2-4 weeks, and males rarely beyond 3 weeks (temperature uncontrolled). The time to develop from egg to adult took just 24-36 days in the laboratory when kept around 21.5 o C. (Nicholas et al 2018). Eggs were observed to be deposited on various surfaces near water or on water, and typically hatched 2-3 days following deposition (Boughalmi et al 2013).…”

“…In New Zealand, they have been noted to be particularly abundant within dairy effluent (Wilson et al 2009). After several moults, the mature larvae crawl out of the liquid material to pupate for 6-10 days (Fischer et al 2006;Nicholas et al 2018). They pupate in surrounding soil and vegetation (Wilson et al 2009).…”

“…There do not appear to be any developed strategies for the management of the drone fly as a field-crop pollinator despite it being easy to rear and maintain in the laboratory (Nicholas et al 2018) as well as being common in agroecosystems (Wilson et al 2009;Stavert et al 2017). To evaluate the potential of managing E. tenax in New Zealand field crops, we reviewed literature describing the efficiency of this species as a crop pollinator, its abundance in New Zealand crops, and those key factors likely to influence abundances, distributions and lifecycle.…”

Facilitation of neural responses to targets moving against optic flow

“…Eristalis tenax hoverflies were reared and maintained as previously described 53 . Prior to electrophysiology, the male hoverfly was immobilized ventral side up using a beeswax and resin mixture.…”