Minimizing Bee (Hymenoptera: Apoidea) Bycatch in Japanese Beetle Traps

Native and introduced bees were attracted to and captured in commercially available Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), traps baited with floral lure components: geraniol, eugenol, and phenethyl propionate [PEP] in Rhode Island, Ohio, and Tennessee. Studies in Rhode Island showed that Bombus impatiens Cresson (Hymenoptera: Apidae) was significantly more attracted to geraniol alone and as a component in floral lure blends than to either eugenol or PEP alone. Xylocopa virginica (L.) (Hymenoptera: Apidae) was more selective in being primarily attracted to traps baited with higher amounts of geraniol in 2016. Removing geraniol from the floral lure blend did not significantly reduce Japanese beetle captures in 2017 and 2018 in Rhode Island and Ohio but did significantly reduce bee captures in Rhode Island in 2017 and 2018. Green, black, brown, and red traps captured significantly fewer bees than clear or standard yellow vane and green cage traps in 2018 in Rhode Island and Tennessee; however, there were no significant differences between Japanese beetle captures in any of the colored or clear traps. Our results show that using all green traps with a lure composed of eugenol and PEP and the Japanese beetle female produced sex pheromone can effectively capture Japanese beetles while minimizing bycatch of bees.

Keanekaragaman serangga pengunjung bunga pada tanaman tumpang sari kedelai dengan tanaman orok-orok (Crotalaria juncea)

Tumbuhan berbunga dapat meningkatkan populasi serangga polinator, yang sekaligus berperan penting dalam meningkatkan hasil tanaman. Tujuan penelitian ini untuk mengetahui pengaruh tumpang sari Crotalaria juncea dengan kedelai terhadap keanekaragaman serangga pengunjung bunga dan polinator alami terhadap hasil kedelai. Penelitian dirancang pada petak tunggal, dengan perlakuan: tanpa C. juncea (kontrol), penanaman C. juncea mengelilingi lahan kedelai, penanaman C. juncea setiap 5 baris kedelai, dan penanaman C. juncea setiap 10 baris kedelai. Pengaruh polinator alami terhadap hasil kedelai diamati melalui penyungkupan tanaman dengan jaring serangga. Hasil penelitian menunjukan, bahwa penanaman C. juncea dapat meningkatkan keanekaragaman serangga pengunjung bunga. Indeks keanekaragaman tertinggi 2,37 tercatat pada petak penanaman C. juncea setiap 10 baris kedelai. Keanekaragaman serangga pengunjung bunga terbanyak, yaitu 18 spesies ditemukan pada perlakuan penanaman C. juncea setiap 5 baris kedelai. Serangga pengunjung bunga yang dominan adalah Coccinella transversalis, Apis mellifera, Xylocopa virginica, Megachile parientina, Megachile relativa, Ropalidia fasciata, dan Vespa sp. Polinator alami (tanpa sungkup) dapat meningkatkan jumlah polong 30,11%, jumlah biji 44,63%, dan berat biji per tanaman 15,44% sehingga berperanan penting pada hasil kedelai.

Ergonomic skew and reproductive queuing based on social and seasonal variation in foraging activity of eastern carpenter bees (Xylocopa virginica)

Reproductive division of labour in social carpenter bees differs from that in classically eusocial insects because reproductive output and ergonomic inputs are positively correlated—dominant females monopolize both foraging and reproduction. We quantified ergonomic skew in the facultatively social bee Xylocopa virginica (L., 1771) (eastern carpenter bee) based on detailed observations of foraging activity by individually marked females in 2009. Unusually for a univoltine bee, this species exhibits a spring foraging phase during which females feed pollen to other adults, probably as part of behavioural interactions to establish dominance hierarchies. During brood-provisioning, foraging in social nests was dominated by one female at a time, with replacement by a succession of foragers as dominants disappeared and were succeeded by a subordinate. The principal foragers (individuals that did the largest share of foraging in each colony) did 85%–100% of all pollen trips, so contributions to pollen-provisioning by female nest mates were highly uneven. Individual foraging rate was unaffected by group size and total colony foraging effort was a function of the number of foragers per group. Transient females that moved to new nests were as successful in achieving dominant forager status as females resident in their natal nests. This evidence indicates that colony social organisation is based on reproductive queues, whereby the first-ranked bee is the dominant forager and subordinates queue for opportunities to replace her.

Climate limitations on the distribution and phenology of a large carpenter bee, Xylocopa virginica (Hymenoptera: Apidae)

We studied climatic correlates of the geographic range of a common large carpenter bee ( Xylocopa virginica (L., 1771)), which reaches farther north than any other Xylocopa in North America. Computational models of the species’ range predicted that summer and winter temperatures limit its northern extent, whereas summer precipitation limits its western extent. We empirically evaluated the climatic constraints imposed by different seasons by examining the winter low-temperature tolerance of X. virginica, and the timing of activity during spring and summer. The bee’s absolute low-temperature tolerance (supercooling point) did not differ between two populations at mid- and high latitudes, and was in excess of requirements of a mean winter minimum temperature. Absolute minimum temperature tolerances may not directly influence the range of X. virginica, whereas other measures of cold tolerance, like exposure duration, might be more relevant. Between years within a study population, spring emergence dates of bees were significantly predicted by spring temperatures and weather (April: 6–11 °C; May: 13–17 °C). Between populations across the bee’s geographic range, bees in warmer climates were observed as much as 2–3 months earlier in the year. This suggests that a major constraint on the bee’s range is the length of the active season, which may be too short for brood development at high latitudes.