Environmental risk assessment of transgene products using honey bee (Apis mellifera) larvae

Abstract

-An environmental concern regarding the cultivation of transgenic crop plants is their effect on non-target organisms. Honey bees are obvious non-target arthropods to be included in a risk assessment procedure but due to their complex social behaviour, testing transgene products on individual bees is not possible in bee colonies. We employed a laboratory larval rearing technique to test the impacts of such transgene products on honey bees. A serine proteinase inhibitor (Kunitz Soybean Trypsin Inhibitor, SBTI), that is a source of insect resistance in transgenic plants, was used as a model insecticidal protein on honey bee larvae reared individually in the laboratory. The addition of 1.0% SBTI (w:w of total protein) to the larval diet created significant additional larval mortality, slowed juvenile development and significantly decreased adult body mass. Our results suggest that the larval rearing technique can be used to monitor direct side-effects of transgene products on individual honey bee larvae.Apis mellifera / risk assessment / larval rearing / transgenic plants / proteinase inhibitor

Modes of honeybees exposure to systemic insecticides: estimated amounts of contaminated pollen and nectar consumed by different categories of bees

“…Some new tests have been proposed to estimate the larvae exposure. Among them, field (Oomen et al, 1992) and semi-field (Leyman et al, 1999;Tornier, 1999) tests do not appear appropriate since larval exposure cannot be controlled, whereas laboratory tests (Malone et al, 2002;Brødsgaard et al, 2003) might be used to estimate adequately the larvae exposure.…”

Does pea lectin expressed transgenically in oilseed rape (Brassica napus) influence honey bee (Apis mellifera) larvae?

“…For workers or drones the diet contains more pollen and honey but less royal jelly than if a queen is being raised (Winston, 1987). Proteins that are present in the hypopharyngeal glands might be transferred to the larvae through the royal jelly provided by the nursing bees (Brødsgaard et al, 2003), but so far there is no evidence that ingested proteins accumulate and can be transferred intact via the hypopharyngeal glands (Malone et al, 2004). Many lectins, however, are stable proteins; insensitive to pH, high temperatures, and resistant to animal proteases (Peumans and Van Damme, 1995).…”

“…proteinase inhibitors (PIs) (Brødsgaard et al, 2003;Burgess et al, 1996;Sagili et al, 2005), Bacillus thuringiensis (Bt) toxins (Arpaia, 1996;Malone et al, 2004) and biotinbinding proteins (Malone et al, 2002). Some have been conducted using transgenic plant material on adults (Babendreier et al, 2005;Liu et al, 2005), but few have considered the effects of transgenic plants on honey bee larval stages (Hanley et al, 2003).…”

Development of hypopharyngeal glands in adult honey bees fed with a Bt toxin, a biotin-binding protein and a protease inhibitor

“…Some purified PIs have been shown to reduce the longevity of both adult and larval honey bees when fed to them at high doses. For example, honey bee larvae fed Kunitz soybean trypsin inhibitor (SBTI) in an artificial diet (1% w:w of total protein) had delayed development and increased mortality compared with those on control diet (Brødsgaard et al, 2003). Since pollen is only a minor component of the natural diet of larval bees (Babendreier et al, 2004), this concentration is likely to be greater than that which bee larvae would be exposed to in transgenic crops.…”