Spinosad in the native stingless bee Melipona quadrifasciata: Regrettable non-target toxicity of a bioinsecticide

Abstract

The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Meliponaquadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components.

Larval exposure to field-realistic concentrations of clothianidin has no effect on development rate, over-winter survival or adult metabolic rate in a solitary bee, Osmia bicornis

“…Because changes in the function of nervous tissue can affect basic autonomic processes such as thermoregulation or respiration (Sláma & Miller, 1987; Kestler, 1991; Belzunces, Tchamitchian & Brunet, 2012; Hatjina et al, 2013; Karise & Mänd, 2015), we measured the metabolic rates of adult bees on the day of emergence. Relatively little is known about the effects of developmental pesticide exposure on adult insect metabolic rates, but acute exposure has been found to alter respiratory rhythms, particularly the propensity to engage in discontinuous gas exchange (Zafeiridou & Theophilidis, 2004; Hatjina et al, 2013; Tomé et al, 2015). We found that while the majority of bees engaged in discontinuous patterns of CO 2 release, a small proportion of bees breathed continuously throughout the observation period, but this propensity was not affected by clothianidin exposure.…”

“…Across a diversity of insects, exposure to neuro-active pesticides has been show to affect rates and patterns of gas exchange, such as the propensity to engage in discontinuous gas exchange (reviewed in Karise & Mänd, 2015). In bees, acute exposure to imidacloprid has been shown to alter abdominal ventilation patterns in adult honey bees (Hatjina et al, 2013) and to increase metabolic rates in the stingless bee Melipona quadrifasciata (Tomé et al, 2015). Accordingly, patterns of respiratory gas exchange are considered a useful physiological measure of an insects’ response to stress, therefore we used flow-through respirometry to examine the metabolic rate and respirometry rhythms of adult O. bicornis exposed to clothianidin as larvae.…”

Dose- and time-dependent effects of oral octopamine treatments on the sucrose responsiveness in stingless bees (Melipona scutellaris)

“…Both neonicotinoids and formamidines mimic the action of biogenic amines (Evans and Gee 1980;Matsuda et al 2001). Consequently, the chronic exposure of bees to sublethal doses of these substances may lead to critical modifications of neural signalling and, eventually, cause behavioural dysfunctions (Farooqui 2013), such as a reduction of respiration rate and flight activity (M. quadrifasciata : Tomé et al 2015), an impairment of olfactory learning and memory, or a decreasing gustatory responsiveness (A. mellifera : Mengoni Goñalons and Farina 2015). Given these interactions between pesticides, biogenic amine signalling, and bee behaviour, the results of our study provide an important baseline for future studies on this topic in stingless bees.…”

Enfraquecimento e perda de colônias de abelhas no Brasil: há casos de CCD?

“…Muitos desses ingredientes ativos, durante sua rota metabólica, afetam diferentes processos celulares que impactam a longevidade, o comportamento e a fisiologia do inseto, e podem causar efeitos individuais e consequências para a colônia ao longo do tempo. Os dados mostram que eles podem afetar o processamento das informações no cérebro de S. postica e Melipona quadrifasciata Tomé et al, 2015). Há dados, inclusive, que mostram que produtos classificados como biopesticidas, como a azadiractina, podem causar deformações nas larvas e causar impactos sobre a manutenção do número de indivíduos da colônia .…”