Effects of an insecticide/fungicide mixture on queen rearing behavior and hypopharyngeal gland morphology in honey bees (Apis mellifera L.) (Hymenoptera: Apidae)

Almond growers in California’s Central Valley routinely use tank mixes of the diamide insecticide chlorantraniliprole and the triazole fungicide propiconazole for pest management during bloom. Although this mix is considered safe for honey bees, I investigated possible sublethal effects on the nursing behavior and hypopharyngeal gland morphology of one-week-old nurse bees. For one week I fed newly emerged adults pollen treated with pesticides at minimum concentrations that had previously been shown to affect honey bee development, after which I caged them with developing queen larvae to assess their ability to tend the larvae. For 15 minutes I observed and recorded the time each individually marked nurse bee spent with her head and thorax inside the queen cell and her abdomen rhythmically contracting. After this observation period, I removed their hypopharyngeal glands for imaging and determined the average width of their acini as a proxy for their ability to produce royal jelly. I found no effect of either pesticide individually, a mixture of the two, or of the insect growth regulator insecticide diflubenzuron, which I chose as a positive control due to its previously demonstrated effect on hypopharyngeal gland morphology, on time spent nursing, or on mean acini width of the hypopharyngeal gland. A significant relationship does exist, however, between the mean width of an individual nurse bee’s acini and the time that that individual bee spent engaged in nursing behavior toward the queen cell to which she was exposed. Based on the hive level effect, however, this study may not be sufficient justification for assuming that sublethal effects are not a concern.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Entomology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Pearlstein, Daniel Joseph

Contributors dc:contributor

• Berenbaum, May R

• Apis mellifera, pesticide, nursing, hypopharyngeal gland, behavior, morphology

Statement dc:rights

• Copyright 2020 Daniel Pearlstein

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/109329

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/109329