Date of Award

12-2015

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Entomology

Advisor

Eleanor Groden

Second Committee Member

Francis A. Drummond

Third Committee Member

William Livingston

Abstract

One method being utilized for detection of the invasive emerald ash borer, Agrilus planipennis (EAB) involves monitoring aggregations of the wasp Cerceris fumipennis for the presence of EAB in their collected prey. Currently there is little information published on its nest structure, phenology, and prey fidelity. The objectives of this research were to: i) monitor C. fumipennis male and female emergence, female prey collection, and number of colonies relative to the accumulation of degree-days (DD) throughout the summer; ii) better understand nest structure, phenology, and prey requirements of C. fumipennis; and iii) investigate C. fumipennis prey selection and fidelity.

Field studies were conducted on C. fumipennis aggregations located at six central Maine sites in 2012, 2013, and 2014. Soil temperatures were monitored continuously and daily degree-day accumulations (base 10°C) were calculated. Sites were monitored for wasp emergence, number of nests, number of wasps, and initiation of mating and prey capture. We excavated nests and measured depth of cells and the number of new cells per nest. The contents of cells were examined for C. fumipennis immature stages and prey. We estimated the mass of beetle prey provisioned and measured the weight of pre-pupae in cells. We identified prey beetles excavated from nests and made comparisons among prey species provisioned within cells.

Mean accumulated DD at first wasp emergence across all sites and years was 594 ± 21 (SE). Male wasps emerged before female wasps 40% of the time. Prey capture was initiated 7-17 days (115 - 287 DD) post emergence, and the peak number of nests occurred in mid-July/early August. There was variation in the number of peak nests at sites between years. Our emergence data demonstrates that the period of flight activity for C. fumipennis and EAB in Maine would overlap.

We excavated 171 nests. The number of new cells per nest and depth of cells varied between sites. The proportion of cells containing eggs generally decreased over a field season, while the proportion of cells containing pre-pupae increased over the field season. There were no significant differences between the numbers of beetles provisioned per egg between sites, but there were differences between the estimated weights of beetles provisioned per egg between sites. Finally, we found that as the estimated provisioned weight increased, the weight of the resulting pre-pupae also increased. Twenty different prey species were identified and we found that 50% to 84% of excavated cells were provisioned with a single genera of beetle prey.

The data presented highlights C. fumipennis's ability to find and to utilize several different hosts as prey items which makes it a good candidate for monitoring EAB and other invasive beetles in the family Buprestidae. We also present data that will aid in the development of rearing techniques for the wasp laying the groundwork for future development of mobile colonies.

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