Effects of selenium on development, survival, and accumulation in the honeybee (Apis mellifera L.)

Abstract

Apis mellifera L. (Hymenoptera: Apidae) is an important agricultural pollinator in the United States and throughout the world. In areas of selenium (Se) contamination, honeybees may be at risk because of the biotransfer of Se from plant products such as nectar and pollen. Several forms of Se can occur in accumulating plants. In the present study, the toxicity of 4 compounds (selenate, selenite, methylselenocysteine, and selenocystine) to honeybee adult foragers and larvae was assessed using dose-response bioassays. Inorganic forms were more toxic than organic forms for both larvae (lethal concentration [LC50] selenate = 0.72 mg L(-1) , LC50 selenite = 1.0 mg L(-1) , LC50 methylselenocysteine = 4.7 mg L(-1) , LC50 selenocystine = 4.4 mg L(-1) ) and foragers (LC50 selenate = 58 mg L(-1) , LC50 selenite = 58 mg L(-1) , LC50 methylselenocysteine = 161 mg L(-1) , LC50 selenocystine = 148 mg L(-1) ). Inorganic forms of Se caused rapid mortality, and organic forms had sublethal effects on development. Larvae accumulated substantial amounts of Se only at the highest doses, whereas foragers accumulated large quantities at all doses. The present study documented very low larval LC50 values for Se; even modest transfer to brood will likely cause increased development times and mortality. The toxicities of the various forms of Se to honeybee larvae and foragers are discussed in comparison with other insect herbivores and detritivores.

Metal contaminant accumulation in the hive: Consequences for whole‐colony health and brood production in the honey bee (Apis mellifera L.)

“…By the conclusion of the experiment, Se‐treated colonies produced no brood. In previous work, high mortality occurred when honey bees were exposed to Se at levels as low as 0.72 mg/L and development slowed at levels as low as 0.6 mg/L . In addition, mortality occurred during the early instars, long before brood would be capped.…”

The bumble bee microbiome increases survival of bees exposed to selenate toxicity

“…Likewise, Hladun et al found that honey bees ( Apis mellifera ) readily foraged on Raphanus sativus plants that were grown in seleniferous soil and collected pollen containing up to 2830 mg kg −1 selenium (Hladun et al, ). Accumulating selenium in the tissues of foraging honey bees has been shown to be detrimental to both the individual forager bees plus the health of the whole colony (Hladun et al, ; ; ). Metals may also have sub‐lethal effects on bees, as foraging efficiency is decreased when honey bees are exposed to manganese (Sovik et al, ) and bumble bees are exposed to nickel (Meindl and Ashman, ; ).…”

Ecological Importance of Insects in Selenium Biogenic Cycling

“…In addition, reduced ability of bees consuming selenate to eat sucrose is observed. Ultimately, effects on survival and foraging behavior may significantly reduce the productivity and longevity of the bee colony and therefore decrement pollination efficiency [35,36]. Additionally, the results of the above studies suggest that trophic transfer via pollen and nectar to insect pollinators is an important route of Se movements in the food webs.…”

“…Therefore decline of bees' population may have substantial environmental consequences. Recent studies [35][36][37] have shown that except pesticides and metals [38][39][40] Se may also be the reason for it. A well-known ecological law of optimum supposes that Se at certain concentrations may promote bee health or may become toxic if ingested in excess.…”