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Simple Summary: Understanding insect dispersal helps us predict the spread of insect pests and their natural enemies. Dispersal can be studied by marking, releasing, and recapturing insects, known as mark–release–recapture (MRR). MRR techniques should be convenient, economical, and persistent. Currently, there are few options for marking small insects, such as parasitic wasps, that do not negatively affect their natural behaviors. We evaluated a marker used as a trap for high-value property (such as bank vaults) for its effectiveness in MRR research with parasitic wasps. This marker is easy to apply and can be detected visually using UV light. We tested this marker on a pest fruit fly and three parasitic wasp species that are used in biological control. We found that the marker lasted for the lifespan of all the insects tested and had little impact on the survival, parasitism, flight, or activity patterns of the wasp species. We were also able to recapture marked wasps up to three weeks after release and 100 m away from the release site, indicating that this technique can be used to track the dispersal of small wasps. Understanding insect dispersal helps us predict the spread of insect pests and their natural enemies. Dispersal can be studied by marking, releasing, and recapturing insects, known as mark–release–recapture (MRR). MRR techniques should be convenient, economical, and persistent. Currently, there are limited options for marking small parasitoids that do not impact their fitness and dispersal ability. We evaluated commercially available fluorescent markers used in forensics. These fluorophores can easily be detected by ultraviolet (UV) light, requiring minimal costs and labor to process the marked specimens. This fluorophore marking technique was evaluated with the pest Drosophila suzukii and three parasitoids: Trissolcus japonicus, Pachycrepoideus vindemiae, Ganaspis brasiliensis (=G. kimorum). We evaluated the persistence of the marks on all the insects over time and examined the parasitoids for impacts on longevity, parasitism, locomotor activity, and flight take-off. The green fluorophore marker persisted for over 20 days on all four species. Marking generally did not consistently reduce the survival, parasitism rate, locomotor activity, or take-off of the parasitoids tested. Marked T. japonicus were recaptured in the field up to 100 m away from the release point and three weeks after release, indicating that this technique is a viable method for studying parasitoid dispersal. [ABSTRACT FROM AUTHOR]

Theory predicts that egg load and foraging activity of insects should be positively related. Species that emerge with a low initial egg load and mature additional eggs as they age may limit initial foraging activity to avoid egg limitation. Similarly, females, which deplete their egg supply through oviposition, should decrease activity immediately afterwards and then increase activity as new eggs are matured.The authors used activity monitors to measure daily locomotor activity separately from exposure to host cues with the stink bug egg parasitoid, Trissolcus japonicus. The authors measured activity and egg load as newly emerged wasps aged and tested whether egg depletion from oviposition would reduce activity.Parasitoid activity increased with age in parallel with egg maturation, with both egg load and activity reaching their maximum about 6–7 days after emergence. Newly emerged wasps began activity later in the day and had lower activity intensity compared with older individuals. When given host experience, females that had laid many offspring, and had thus depleted their egg loads, unexpectedly increased their activity for up to 3 days.The present study results challenge the generally accepted positive relationship between foraging activity and egg load, suggesting that this relationship may be secondary to host patch quality. The authors provide evidence that host patch quality can influence not only within‐patch but also between‐patch foraging activity.Plastic responses in activity patterns may allow parasitoids to better exploit rich host environments while minimising foraging costs and decreasing likelihood of egg limitation in low‐quality environments. [ABSTRACT FROM AUTHOR]

The brown marmorated stink bug, Halyomorpha halys (Stål), has become a well-known pest to growers and homeowners since its 1996 introduction to the United States. A classical biocontrol programme is under development using the egg parasitoid Trissolcus japonicus. Widespread implementation of biocontrol requires efficient mass rearing, which is constrained by the availability of fresh H. halys eggs. In this study, parasitism rate, developmental time, sex ratio and size were compared between wasps reared on fresh versus frozen, newly laid (<1 d old) versus variably aged (0-3 d old), and frozen egg masses stored ≤4 y. Frozen eggs yielded 56-65% fewer wasps, with parasitism rate decreasing 1-3% per month stored. Parasitism rate, sex ratio and developmental time were comparable between newly laid and variably aged eggs. Freezing eggs for any duration did not affect sex ratio or weight of emerged wasps, but delayed emergence 5-6 d. To simulate deployment of sentinel eggs in the field, we incubated frozen eggs at 20°C and 30°C for 1-9 d before exposing them to T. japonicus, then evaluated parasitism trends. Trissolcus japonicus parasitism rate decreased 5-8% per day incubated, unhatched wasps increased 9% per day incubated and sex ratio was not impacted. Variably aged, frozen and longer stored eggs can be used for T. japonicus rearing and experimentation without affecting emerged wasp sex ratio or size within one generation, but have lower parasitism and slower development. Frozen sentinel eggs are effective <3-5 d, especially in hot conditions. [ABSTRACT FROM AUTHOR]

The azalea lace bug, Stephanitis pyrioides Scott, 1874, is a serious pest of rhododendrons and azaleas. While it has been present in the Eastern U.S.A. since 1915, it was only detected in the Pacific Northwest in 2008-2009, where it has become a serious emerging pest. Although its biology and control methods have been examined in the eastern states, little information is available about how to manage this pest in western states. A 2.4-year survey was conducted to document its phenology at 3-8 sites in the Willamette Valley of Oregon and check for the presence of natural enemies specializing on lace bugs that are found in the East Coast. Similar to prior studies, eggs were the predominant overwintering stage in Oregon. Three generations of S. pyrioides were observed during monthly inspections of infested plants, while ~3.5 generations were estimated by degree-day (DD) calculations based upon 11.2°C and 33°C as the lower and upper thresholds, respectively. Egg hatch was observed as early as April at 156 DD based on a 10.2°C lower threshold specific for egg development. These results suggest that early season management in March through May might target overwintered eggs to prevent hatch or target the young nymphs that emerge. Neither of the exotic natural enemies established in the East Coast, the egg parasitoid, Anagrus takeyanus Gordh, 1977, or the predatory mirid, Stethoconus japonicus Schumacher, 1917, were detected when rearing S. pyrioides from eggs or taking shake samples from infested leaves. Future biological control efforts should focus on other natural enemies. [ABSTRACT FROM AUTHOR]