Format

Send to

Choose Destination
Environ Entomol. 2016 Feb;45(1):245-51. doi: 10.1093/ee/nvv152. Epub 2015 Sep 18.

Thermoperiodism Synchronizes Emergence in the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae).

Author information

1
USDA-ARS Red River Valley Agricultural Research Center, Biosciences Research Laboratory, 1605 Albrecht Blvd., Fargo, ND 58102-2765 (george.yocum@ars.usda.gov; Joseph.Rinehart@ars.usda.gov; ian.yocum@ars.usda.gov; william.kemp@ars.usda.gov), george.yocum@ars.usda.gov.
2
USDA-ARS Red River Valley Agricultural Research Center, Biosciences Research Laboratory, 1605 Albrecht Blvd., Fargo, ND 58102-2765 (george.yocum@ars.usda.gov; Joseph.Rinehart@ars.usda.gov; ian.yocum@ars.usda.gov; william.kemp@ars.usda.gov).
3
Department of Biological Sciences, North Dakota State University, PO Box 6050, Dept. 2715, Fargo, ND 58108-6050 (kendra.greenlee@ndsu.edu).

Abstract

Alfalfa seed production in the northwestern United States and western Canada is heavily dependent upon the pollinating services of Megachile rotundata (F.) (Hymenoptera: Megachilidae). M. rotundata females nest in cavities either naturally occurring or in artificial nesting blocks. Because of the physical nature of the nest, M. rotundata brood may have limited to no exposure to photoperiodic cues in order to regulate important circadian functions. Therefore, various thermoperiod regimes were used to characterize the possible role of thermoperiodism in synchronizing M. rotundata adult emergence. Adult emergence was monitored using a microprocessor-controlled event logger. Incubating bees under constant 29°C and darkness resulted in an arhythmic adult emergence pattern. Exposing developing M. rotundata to a thermoperiod synchronized emergence to the beginning of the thermophase and decreased the total number of days required for all adults to emerge. The amplitude of the thermoperiod regulated the timing of peak emergence in relationship to the increase in temperature. A thermoperiod amplitude of only 2°C was sufficient to synchronize peak adult emergence to take place during the rise in temperature. Increasing the amplitude of the thermoperiod to 4 or 8°C caused a positively correlated shift in peak emergence to later in the thermophase. Brood stored under constant 29°C and darkness for different durations (May or June early in the growing season or July or August late in the growing season) or under a fluctuating thermal regime (base temperature of 6°C and daily 1-h pulse of 20°C until September or November) maintained their capacity for entraining emergence timing by thermoperiodism.

KEYWORDS:

alfalfa leafcutting bee; fluctuating thermal regime; insect storage

PMID:
26385932
DOI:
10.1093/ee/nvv152
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center