Natural enemies often cause significant levels of mortality for their prey and thus can be important agents of natural selection. It follows, then, that selection should favor traits that enable organisms to escape from their natural enemies into “enemy-free space” (EFS). Natural selection for EFS was originally proposed as a general force in structuring ecological communities, but more recently has become conceptually narrow and is typically only invoked when studying the evolutionary ecology of host plant use by specialized insect herbivores. By confining the application of EFS to specialist herbivores, its potential value to community and evolutionary ecology has been marginalized. As a first step toward exploring the potential explanatory power of EFS in structuring ecological niches of higher trophic-level organisms, we consider host use by parasitoids. Here, we present three distinct mechanisms from our studies of caterpillar host—parasitoid interactions suggesting that parasitoids may be under selection to exploit traits of their hosts and the plants on which those hosts feed to garner EFS for their developing offspring. The neglect of EFS as a top—down selective force on host use by parasitoids may be a serious limitation to basic and applied ecology, given the great diversity of parasitoids and their significance in controlling herbivore populations in both natural and managed ecosystems. Parasitoids and other mesopredators represent excellent candidates for further developments of EFS theory and testing of its broader importance.

Spatial and temporal variation in the density of the Aroga moth, Aroga websteri Clarke (Lepidoptera: Gelechiidae), and in its damage to its host plant, big sagebrush (Artemisia tridentata Nuttall), were examined at 38 sites across a shrub steppe landscape in mountain foothills of northern Utah. Sites were sampled from 2008 to 2012 during and after an outbreak of the moth, to assess whether and how local variation in moth abundance, survivorship, and damage to the host plant was accounted for by sagebrush cover, elevation, slope, aspect, or incident solar radiation. As moth numbers declined from a peak in 2009, individual sites had a consistent tendency in subsequent years to support more or fewer defoliator larvae. Local moth abundance was not correlated with sagebrush cover, which declined with elevation, and moth survivorship was highest at intermediate elevations (1,800–2,000 m). North-facing stands of sagebrush, characterized by lower values of incident solar radiation, were found to be especially suitable local habitats for the Aroga moth, as reflected in measures of both abundance and feeding damage. This high habitat suitability may result from favorable microclimate, both in its direct effects on the Aroga moth and in indirect effects through associated vegetative responses. North-facing sites also supported taller and more voluminous sagebrush plants in comparison to south-facing sites. Thus, the moth is reasonably predictable in the sites at which it is likely to occur in greatest numbers, and such sites may be those that in fact have most potential to recover from feeding damage.

Charipinae hyperparasitoids affect effectiveness of the primary parasitoids of aphids by decreasing their abundance and modifying their behavior. As a result, increase of aphid populations can cause severe yield losses in some crops. Therefore, ecological studies on the subfamily Charipinae have a great economical and biological importance. Host specificity of these hyperparasitoids is still under debate and for many Charipinae species very little is known about their trophic relations. Here, we give a comprehensive overview of the trophic relationships between the Charipinae species of the genus Alloxysta Förster and their aphid and primary parasitoids hosts, worldwide. Within this subfamily, Alloxysta arcuata (Kieffer), Alloxysta brevis (Thomson), Alloxysta fuscicornis (Hartig), and Alloxysta victrix (Westwood) are the most generalist species sharing many aphid hosts, while for primary parasitoid hosts these are A. arcuata, A. brevis, Alloxysta pleuralis (Cameron), and A. victrix. Alloxysta citripes (Thomson), Alloxysta halterata (Thomson), Alloxysta leunisii (Hartig), and Alloxysta ramulifera (Thomson) appear, up to now, as the most specialized in relation to the primary parasitoid hosts. Primary parasitoids of the genera Aphidius Nees, Lysiphlebus Förster, Praon Haliday, and Trioxys Haliday are the most common hosts for Alloxysta species, and the common host aphid species belong to the genera Aphis L., Uroleucon Mordvilko, Myzus Passerini, and Sitobion Mordvilko. Host range is analyzed for each Alloxysta species, as well as the extent of overlap between them. We used Jaccard's distance and a hierarchical cluster analysis to determine the host range dissimilarity. A permutation test has been applied to analyze if the host range dissimilarity is significantly different from what is expected by chance. We have calculated additional qualitative measures that complement well the Alloxysta niche overlap analysis and evaluated their host specificity using different indices and bipartite networks.

Exotic ants have become invasive in many regions around the world, with variable ecological impacts. Postinvasion, native ant communities are often found to be depauperate, though the causes of this apparent lack of coexistence are rarely well known. Myrmica rubra (L.), a Palearctic Myrmecine ant, is currently expanding its range as an invasive in North America. This aggressive ant forms dense, patchy local infestations and appears to aggressively displace native ant fauna. We measured behavioral interactions and rates of recruitment in experimental field assays pitting native foragers against captive colonies of M. rubra at tuna-jelly or aphid baits in uninfested areas of Mt. Desert Island, ME. Behavioral interactions were idiosyncratic with respect to the native opponent, but M. rubra generally showed significantly higher levels of recruitment, aggression, and displacement of native foragers. As with other invasive ant species shown to have broken the “dominance—discovery trade-off,” M. rubra was consistently faster to discover baits and disproportionately displaced native foragers, providing a plausible proximate mechanism for native ant exclusion. Finally, we surveyed ant recruitment at baits for 24 h in August 2004 at four sites with varying M. rubra abundance but found little evidence of temporal niche partitioning. Taken together, these results indicate competitive superiority by M. rubra with respect to native ant communities of the northeastern North America and suggest direct aggression and competitive exclusion at food resources can lead to local native displacement.

The Atlantic Forest (AF) is considered the most fragmented and endangered Brazilian biome. The diversity of phytophagous insects increases after disturbances in forests, and it was hypothesized the Pentatomidae can furnish ecologically reliable information in terms of diversity in response to the changes occurring in AF. Our aim was to quantify the response of assemblages of Pentatomoidea to gradient of human disturbance in two vegetation types of the AF—dense ombrophilous forest (DOF) and mixed ombrophilous forest (MOF). Twelve transects were grouped into environmental classes, namely open, intermediate, and closed. Overall, 1,017 pentatomoids were sampled, representing 64 species. The open environment was more abundant than closed environment, though it is expected that Pentatomoidea respond with increasing abundance when under light or moderate disturbance. The MOF was more abundant than DOF, and the composition differed between both of them. Given the differences in composition between MOF and DOF, abiotic variables are important factors acting as environmental filters for Pentatomoidea, not just directly on the insects, but probably also on the nutritional support of their host plants.

Honeydew is abundant in many ecosystems and may provide an alternative food source (a buffer) for pollinators during periods of food shortage, but the impact of honeydew on pollination systems has received little attention to date. In New Zealand, kānuka trees (Myrtaceae: Kunzea ericoides (A. Rich) Joy Thompson) are often heavily infested by the endemic honeydew-producing scale insect Coelostomidia wairoensis (Maskell) (Hemiptera: Coelostomidiidae) and the period of high honeydew production can overlap with kānuka flowering. In this study, we quantified the sugar resources (honeydew and nectar) available on kānuka and recorded nocturnal insect activity on infested and uninfested kānuka during the flowering period. Insects were abundant on infested trees, but flowers on infested trees received fewer insect visitors than flowers on uninfested trees. There was little evidence that insects had switched directly from nectar-feeding to honeydew-feeding, but it is possible that some omnivores (e.g., cockroaches) were distracted by the other honeydew-associated resources on infested branches (e.g., sooty molds, prey). Additional sampling was carried out after kānuka flowering had finished to determine honeydew usage in the absence of adjacent nectar resources. Moths, which had fed almost exclusively on nectar earlier, were recorded feeding extensively on honeydew after flowering had ceased; hence, honeydew may provide an additional food source for potential pollinators. Our results show that honeydew resources can impact floral visitation patterns and suggest that future pollinator studies should consider the full range of sugar resources present in the study environment.

The goals of this study were to identify pupal parasitoids of the asparagus miner, Ophiomyia simplex Loew (Diptera: Agromyzidae), and examine the effect of different diets and floral resources on the lifespan of adult asparagus miners and their parasitoids. We also measured the effect of parasitism on stem damage caused by the asparagus miner. The identity and abundance of the parasitoids of the asparagus miner were determined in asparagus fields in Michigan from weekly asparagus miner pupal collections during the 2010–2013 seasons. Twelve species of hymenopterous parasitoids were reared from asparagus miner pupae, including Chorebus rondanii (Giard) (Ichneumonoidea: Braconidae), 10 species in three families of Chalcidoidea, and one species of Bethylidae (Chrysidoidea), that represent new host records for the asparagus miner. C. rondanii and Thinodytes cephalon (Walker) (Pteromalidae) were the most common parasitoids. The effects of different diets and flowers on the lifespan of the pest and parasitoid adults were also evaluated. Buckwheat resulted in the shortest life span for the asparagus miner, whereas Riddell's goldenrod significantly increased its lifespan relative to the control. Parasitoid lifespan was doubled when individuals were fed sugar-rich diets. In the field, parasitoids preferred stems that contained more pupae and damage. The two most commonly reared parasitoids should be considered as targets for future conservation biological control efforts of the asparagus miner.

The lettuce aphid, Nasonovia ribisnigri (Mosley), is an economically important pest of lettuce worldwide. Little documentation exists for the control efficacy of aphid parasitoids against N. ribisnigri. This laboratory study evaluated three commercially available parasitoid species: Aphidius colemani (Viereck), Lysiphlebus testaceipes (Cresson), and Aphelinus abdominalis (Dalman) for their mortality impact on N. ribisnigri. The green peach aphid Myzus persicae (Sulzer) was included as a reference aphid. The study showed that A. abdominalis successfully parasitized 39 and 13% of the offered N. ribisnigri and M. persicae, respectively, within a 24-h exposure period. In contrast, none of the lettuce aphids exposed to Ap. colemani or L. testaceipes were successfully parasitized, whereas 60 and 3.5% of M. persicae, respectively, were successfully parasitized within a 6-h exposure period. Lettuce aphid mortality due to incomplete parasitization was 26 and 31% when exposed to Ap. colemani and L. testaceipes, respectively, with corresponding values for M. persicae being 5 and 10%, respectively. Mortality as a result of incomplete parasitization when aphids were exposed to A. abdominalis was low for both aphid species. The total mortality inflicted by A. abdominalis within a 24-h exposure period was 51% for the lettuce aphids and significantly less (19%) for green peach aphids. In contrast, Ap. colemani inflicted a higher mortality in M. persicae (65%) compared with N. ribisnigri (26%) within a 6-h exposure period. L. testaceipes caused a greater mortality in N. ribisnigri as compared with M. persicae. This study concludes that A. abdominalis has the potential to be used against N. ribisnigri in inoculative biocontrol programs as compared with the other parasitoid species based on successful parasitization.

The population dynamics of the cabbage aphid, Brevicoryne brassicae (L.), its parasitoid, Diaeretiella rapae McIntosh, and hyperparasitoids, Pachyneuron spp., were quantified under field conditions during 2011–2013, by examining synchronization, parasitoid: aphid ratio, possible effect of density on the finite rate of increase, and spatial coincidence. The rates of parasitism and hyperparasitism were based on rearing field-collected mummies and live parasitized aphids, and density of the aphid were estimated using heat extraction and subsampling techniques. Only one parasitoid, D. rapae (80% on average), and two hyperparasitoid species from the genus of Pachyneuron (6.5% on average), namely Pachyneuron aphidis (Bouché) and Pachyneuron groenlandicum (Holmgren), were reared from the aphid mummies. Significant Pearson's time lagged correlations for percentage parasitism versus aphid density and for percentage hyperparasitism versus mummy density indicated that 2–3 wk is needed for D. rapae and Pachyneuron spp. to show impact on their respective host's population. In early spring, the parasitoid: aphid ratio was low (0.11 on average) while aphid density was increasing. Based on Taylor's power law, D. rapae and Pachyneuron spp., as well as B. brassicae, had an aggregated distribution among canola plants. Moreover, a high degree of spatial overlap was found between D. rapae and B. brassicae and between Pachyneuron spp. and D. rapae. In general, the parasitoid had good spatial coincidence with its aphid host but because of a lack of parasitoid-host synchronization and low parasitoid: aphid ratio, impact on the host population was low.

A study using Metarhizium brunneum Petch fungal bands designed to improve delivery of conidia to adult Asian longhorned beetles, Anoplophora glabripennis (Motschulsky), was conducted to determine how a time delay between exposure to infective conidia and pairing of male and female beetles would affect the ability to successfully transfer lethal doses of conidia to a mate. We measured conidial load at the time of mate pairing (0, 4, 24, 48 h postexposure) and assessed its effect on beetle mortality. Conidial load per beetle decreased across the four sampling times, and there was no effect of beetle sex on conidial load. At all time periods postexposure, beetles that climbed across fungal bands carried enough conidia that at least some of their indirectly exposed mates died of mycosis. For indirectly exposed beetles, mortality decreased significantly as the time delay increased from 0 to 48 h, and this was independent of beetle sex. Median survival time was only 11.5 d for females indirectly exposed immediately after their mate had been exposed, but >3 wk when there was a 48-h delay before pairing. Generally, beetles exposed directly to fungal bands died faster than their indirectly exposed mates. In contrast to the pattern seen for indirectly exposed beetles, beetles exposed directly to fungal bands showed no change in survival times with a delay between exposure and pairing. Median survival times of exposed females and males were generally similar, at 10.5–12.5 d.

Insect herbivores frequently move about on their host plants to obtain food, avoid enemies and competitors, and cope with changing environmental conditions. Although numerous plant traits influence the movement of specialist herbivores, few studies have examined movement responses of generalist herbivores to the variable ecological conditions associated with feeding and living on an array of host plants. We tested whether the movement patterns of two generalist caterpillars (Euclea delphinii Boisduval and Acharia stimulea Clemens, Limacodidae) differed on six different host tree species over 10 d. Because these tree species vary in the range of light environments in which they commonly grow, we also compared the movement responses of E. delphinii caterpillars to two contrasting light environments, sun and shade. For both caterpillar species, multiple measures of movement varied significantly among host tree species. In early censuses, movement rates and distances were highest on red oak and black cherry and lowest on white oak. Site fidelity was greatest on white oak and lowest on black cherry. Movement of both caterpillar species varied inversely with mean predator density on five of the six host trees. Other ecological predictors (e.g., leaf size and the density of other herbivores) were unrelated to movement. Light environment altered behavior such that caterpillars in the shade moved and fed more often, and moved greater distances, than caterpillars in the sun. Although the mechanism(s) promoting or inhibiting movement under these different conditions requires further study, the consequences of increased movement for caterpillar development and mortality from natural enemies are discussed.

Modern agriculture relies on domesticated pollinators such as the honey bee (Apis mellifera L.), and to a lesser extent on native pollinators, for the production of animal-pollinated crops. There is growing concern that pollinator availability may not keep pace with increasing agricultural production. However, whether crop production is in fact pollen-limited at the field scale has rarely been studied. Here, we ask whether commercial highbush blueberry (Vaccinium corymbosum L.) production in New Jersey is limited by a lack of pollination even when growers provide honey bees at recommended densities. We studied two varieties of blueberry over 3 yr to determine whether blueberry crop production is pollen-limited and to measure the relative contributions of honey bees and native bees to blueberry pollination. We found two lines of evidence for pollen limitation. First, berries receiving supplemental hand-pollination were generally heavier than berries receiving ambient pollination. Second, mean berry mass increased significantly and nonasymptotically with honey bee flower visitation rate. While honey bees provided 86% of pollination and thus drove the findings reported above, native bees still contributed 14% of total pollination even in our conventionally managed, high-input agricultural system. Honey bees and native bees were also similarly efficient as pollinators on a per-visit basis. Overall, our study shows that pollination can be a limiting factor in commercial fruit production. Yields might increase with increased honey bee stocking rates and improved dispersal of hives within crop fields, and with habitat restoration to increase pollination provided by native bees.

Mosquitoes are one of the most globally important insect pests and vectors of human pathogens, and their populations may be facilitated or inhibited by anthropogenic environmental change. Invasive plant species are an important management concern and environmental modifier in many ecosystems; these plant invasions have the potential to exacerbate or diminish mosquito populations. The purpose of this study was to assess potential effects of a highly invasive plant, Lonicera maackii, on a common mosquito species Culex pipiens L., which is an important pathogen vector in the United States. Three microcosm assays were conducted to determine the responses of C. pipiens life history attributes of larval survivorship, growth, and pupation when subjected to leachate from two native plant leaves (Platanus occidentalis and Acer saccharum) and both the leaves and flowers of L. maackii. Only C. pipiens larvae exposed to L. maackii leachate pupated and emerged as adults. However, in all three assays there were statistically significant differences in survivorship and body size change among treatments, and in each assay the highest survivorship and maximum larval size was found in the L. maackii leachate treatments, suggesting positive effects on certain life history traits. This study is one of the first to demonstrate the potential facilitative effect of this invasive plant species on an insect vector and suggests that plant invasion could have positive feedbacks into mosquito population dynamics and, ultimately, human disease.

Tiphia vernalis Rohwer and Tiphia popilliavora Rohwer are ectoparasitoids of root-feeding larvae of the Japanese beetle, Popillia japonica Newman, and oriental beetles, Anomala orientalis Waterhouse (Coleoptera: Scarabaeidae). Little is known about the influence of host species and location in the host detection ability of tiphiid wasps. In this study, we examined the response of female T. popilliavora wasps, an understudied Tiphia species, to potential host stimuli using dual choice tests in an observation chamber filled with soil. T. popilliavora wasps were able to successfully discriminate the trails containing body odor or frass of P. japonica grubs from trails without cues. Frass trails of P. japonica grubs elicited stronger responses than body odor trails. We also examined the preference of host cues by tiphiid wasps using dual choice behavioral assays. Both T. vernalis and T. popilliavora wasps did not show preference toward trails that either contained P. japonica or A. orientalis cues. In addition, we also determined the detection of host cues by tiphiid wasps in a dual-choice test for cues presented at varying soil depths. Wasps were able to successfully discriminate between the Y-tube arms with and without cues when the cues of P. japonica were buried at a depth of 2 cm. In contrast, both Tiphia species were unable to distinguish between the Y-tube arms with and without cues when the cues were buried at a depth of 5 cm. Thus, our findings suggest that once Tiphia wasps land on the ground, they can detect the presence of their specific hosts, just below the soil surface by exploiting the kairomones present in grub body odor trails and frass and once the wasps are in the soil, they use the same cues to direct themselves to the host grubs.

The dispersal characteristics of a biological control agent can have direct implications on the ability of that agent to control populations of a target host. Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is a parasitic wasp native to eastern Asia that has been introduced into the United States as part of a classical biological control program against the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). We used computer-monitored flight mills to investigate the role of age, feeding status, mating status, and size on the flight capacity of female T. planipennisi over a 24-h period. We also compared flight capacity between sexes. Flight distance of female T. planipennisi representative of populations released in the biological control program averaged 1.26 km in 24 h with a maximum flight of just over 7 km. Median flight distance, however, was 422 m. The flight capacity of females fed a honey—water solution was 41× that of females provided only water, who flew very little. Larger females were capable of flying farther distances, but age did not affect the flight capacity of females up to 70 d posteclosion. Females dispersed 6× farther than did their smaller, male counterparts. The implications of our findings to host—parasitoid interactions and release protocols for distributing T. planipennisi are discussed.

The bark scorpion, Centruroides sculpturatus Ewing, is a nocturnal, cryptic, nonburrowing, mobile species that is common in urban landscapes spanning the desert southwest. Bark scorpions are often found in dense localized populations in cities, but the question of whether this is because the species is metabolically movement limited or choose to aggregate has not been addressed. Field observations lead us to believe that the scorpions move very little. Their ability to move is tested here. A circular pacing ring was constructed to observe the distance individuals could move in 2 h under both dark and light conditions. Observations under light motivate the arthropods to move, and significantly greater distances were observed in light trials, the maximum travel distance being 104.37 m, while the maximum distance in dark trials was 14.63 m. To monitor movement in the field, telemetry tags were used to mark female and male scorpions over 21 d during which relocation distances were recorded daily. Additionally, 12-h and 6-h overnight observational periods took place during which, scorpion movements were recorded hourly. Overall, it was found that scorpions moved significantly more in the pacing ring than in the field, indicating that field individuals are not moving at their maximum potential. Movement limitation does not explain their distribution pattern. In both the pacing ring and field, gender and pregnancy status had significant influence on distances moved. We conclude that C. sculpturatus is capable of much greater movement than is typically observed in the field.

Stink bugs are the primary arthropod soybean pests in the southern United States. Historically, important stink bug species damaging soybeans in the southern United States included the southern green stink bug Nezara viridula (L.), the green stink bug Chinavia hilaris (Say), and the brown stink bug Euschistus servus (Say) (Hemiptera: Pentatomidae). The redbanded stink bug, Piezodorus guildinii (Westwood), has recently become an economic pest of soybean in the southern region of the United States, especially in Louisiana and Texas. Little is known about current stink bug species composition and relative abundance in Texan soybean agro-ecosystems. To fill this gap, commercial soybean fields in the Upper Gulf Coast of Texas were sampled weekly during the growing season using a sweep net throughout R2 (full flowering) to R7 (beginning maturity) from 2011 to 2013. Adults and nymphs (third, fourth, and fifth instars) of redbanded stink bug, southern green stink bug, green stink bug, and brown stink bug were counted per 25 sweeps. The relative abundance of redbanded stink bug was significantly higher than any other stink bug species throughout 2011–2013. Over 65% of the total population of major stink bugs collected during this period were redbanded stink bugs and ≈19% were southern green stink bugs. The highest redbanded stink bug densities and the highest ratio of redbanded stink bug nymphs to adults were recorded at R7. Results from this study show that redbanded stink bug has become the predominant stink bug species in soybean in the Upper Gulf Coast of Texas.

Studies were conducted to assess glacial acetic acid (GAA) with various host plant volatiles (HPVs) and the sex pheromone, (E,E)-8, 10-dodecadien-1-ol, of codling moth, Cydia pomonella (L), as lures in traps for tortricid pests that often co-occur in tree fruits in the western United States. In addition to codling moth, field trapping studies were conducted with oriental fruit moth, Grapholita molesta (Busck), obliquebanded leafroller Choristoneura rosaceana (Harris), the leafroller Pandemis pyrusana Kearfott, and the eyespotted budmoth, Spilonota ocellana (Denis and Schiffermüller). HPVs included ethyl (E,Z)-2,4-decadienoate (pear ester), (E)-4,8dimethyl-l,3,7-nonatriene, butyl hexanoate, (E)-β-ocimene, (E)-β-farnesene, and farnesol. Three types of GAA co-lures differing in a 10-fold range in weekly evaporation rates were tested. The evaporation rate of GAA co-lures was an important factor affecting moth catches. The highest rate tested captured fewer codling moth but more leafrollers and eyespotted budmoth. GAA co-lures caught both sexes of each species. The field life of butyl hexanoate and (E)-β-ocimene lures were much shorter than pear ester or sex pheromone lures. Adding GAA to pear ester or to (E)-β-ocimene significantly increased the catches of only codling moth or oriental fruit moth, respectively. Combining pear ester or (E) -β-ocimene with GAA did not affect the catch of either species compared with the single more attractive HPV. Adding HPVs to GAA did not increase the catches of either leafroller species or eyespotted budmoth. Traps baited with pear ester, sex pheromone, and GAA for monitoring codling moth were also effective in classifying pest pressure of both leafroller species within orchards.

Climate variability is expected to have an influence on the population of Hessian fly, Mayetiola destructor Say (Diptera: Cecidomyiidae), a serious insect pest of winter wheat in the southeastern United States. This study had two objectives: 1) to examine the effects of El Niño-Southern Oscillation (ENSO) on Hessian fly infestation and 2) to develop a weather-based Hessian fly infestation model for wheat yield loss prediction. At least 20 years of Hessian fly infestation and wheat yield records from two locations in South Georgia were used for this study. The yearly values of infestation were separated by ENSO phase and tested to assess the infestation differences across ENSO phases. Each year, yield losses from infestation were calculated by subtracting the yields of resistant varieties from those of susceptible ones. The yield losses were then separated by ENSO phase and tested. Multiple regression analyses were conducted to identify the contribution of monthly weather variables and changes in wheat acreage to Hessian fly infestation. Results showed that Hessian fly infestation and yield losses were greatest during the La Niña and least during the El Niño phase. The weather conditions that significantly increased the risk for infestation were those of the August—February period. The risk of infestation was higher during August—September under wetter, cooler conditions and during October—February under drier, warmer conditions. These findings could help wheat growers reduce the risk of infestation in the years that are expected to have more infestation through the adoption of necessary mitigation measures before the crop season.

Daily distributions of eclosion and mating activities of Pseudopidorus fasciata Walker (Lepidoptera: Zygaenidae) were recorded under natural and various laboratory conditions. Eclosion of this insect exhibited circadian gating in constant darkness (DD) but not in constant light (LL) at 28°C. Under natural conditions, the majority of adults emerged in midmorning with an eclosion peak around 1000 hours. The eclosion distribution was significantly affected by ambient temperature but not by photoperiod under laboratory conditions. Eclosion was more spread out at 22°C than at higher temperatures, and peak eclosion times were advanced at higher temperatures up to 30°C. Under natural and laboratory diurnal cycles, adults of P. fasciata preferred to mate at dusk, within a few hours before the start of the scotophase. Photoperiod and ambient temperature interacted in regulating the mating distribution in P. fasciata. Mating rhythmicity disappeared under DD and LL, under which the insect either mated arrhythmically (DD) or barely mated (LL). Overall, eclosion rhythm in this insect was predominantly regulated by temperature rather than photoperiod, whereas photoperiod appeared to be more influential than temperature in rhythmic gate of mating patterns.