The golden twin-spot moth or tomato looper, Chrysodeixis chalcites (Esper), is a polyphagous and worldwide pest that causes important aesthetic damages to banana fruits in the Canary Islands. The life history parameters of C. chalcites were determined under laboratory conditions in base on the age-stage, two-sex life table at 15, 20, 25, 30, and 35°C, 65% relative humidity (RH), and a photoperiod of 16:8 (L:D) h, when it was reared on a semi-synthetic diet. The results show that C. chalcites was able to develop and survive from 15 to 30°C, but no development occurred at 35°C. Developmental threshold temperatures of the egg, larval, pupal, and total preoviposition stages were 10.42, 11.73, 11.22, and 9.42°C, respectively, and their effective accumulated temperatures were 58.31, 265.96, 118.57, and 562.39 degree-days, respectively. The adult longevity was reduced with increasing temperature, which ranged between 16.27 and 34.85 d for females and between 14.27 and 35.21 d for males. The highest values of net reproductive rate (R₀) and fecundity were observed at 25°C, with 232.70 offspring and 1,224.74 eggs, respectively. Both the intrinsic rate of increase (r) and finite rate of increase (λ) increased significantly and mean generation time (T) decreased significantly with increasing temperature. These results provide useful information that will allow predicting the impact of climate change on the distribution and population dynamics of C. chalcites and developing successful integrated management programs.

Delayed mating is an effective strategy that can decrease the fecundity of a pest by reducing the time that females have to mate. This disruption does not completely inhibit mating and may lead to multiple matings. The effects of delayed mating with multiple partners on different indexes of mating in female and male Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) were determined in this study. The delay in mating significantly decreased the number of matings and the mating success of both sexes and the male contribution to reproduction. Compared with the effect on female fecundity, the delayed mating with multiple partners had a greater effect on the male mate contribution to fecundity. The longevity of females and males increased significantly with a 72 h delay in mating. Linear regression analysis showed negative relationships between delayed mating and fecundity and number of matings in both sexes. Thus, delayed mating with multiple partners can disrupt the mating and reproductive potential of S. litura.

Integration of biological control with other management tactics such as prescribed burning is often important for successful invasive weed control. A critical step in this integration is determining whether the agent can colonize postburn growth of the weed. Here, we investigated postburn colonization by biological control agents on regrowth of the invasive vine Lygodium microphyllum (Cav.) R. Br. (Lygodiaceae, Old World climbing fern) in Florida. We monitored regrowth and subsequent colonization of two agents already established in Florida—the gall-inducing mite Floracarus perrepae Knihinicki and Boczek (Acariformes: Eriophyidae) and the foliage-feeding moth Neomusotima conspurcatalis Warren (Lepidoptera: Crambidae)—following three prescribed burns. We provide the first report of natural colonization by the F. perrepae mite and N. conspurcatalis moth on postburn L. microphyllum regrowth, and this colonization typically began 5–9 mo postburn. Furthermore, we report that L. microphyllum can recover to prefire levels of percent cover in as little as 5 mo. Our findings indicate that biological control of L. microphyllum has the potential to be integrated with prescribed burns.

The weevil Metamasius spinolae (Gyllenhal) is the most important insect pest of cultivated prickly pear in Mexico. A previous work reported that the pheromone of this weevil species was composed by three components. In this study, we reinvestigated the aggregation pheromone of M. spinolae using gas chromatography-electroantennography and gas chromatography–mass spectrometry to locate and identify new potential pheromonal compounds. The behavioral activity of identified compounds was evaluated in laboratory and field trials. Metamasius spinolae males released four compounds: 2-methyl-4-heptanone, 6-methyl-2-hepten-4-one, 2-methyl-4-octanone, and 2-hydroxy-2-methyl-4-heptanone. In the laboratory assays, depending on the concentration, the compounds were attractive, neutral, or repellent to M. spinolae. Field evaluation showed that traps baited with 2-hydroxy-2-methyl-4-heptanone singly or in most of the binary or tertiary blends where this compound was present captured a higher number of M. spinolae compared to live males and the other compounds identified. In conclusion, our results indicate that 2-hydroxy-2-methyl-4-heptanone is the main component of the aggregation pheromone of M. spinolae. We suggest that this compound should be used for developing a monitoring or a mass-trapping system for M. spinolae.

Immature guava fruits (Psidium guajava L.) of commercial orchards in Mexico are affected by adults of Conotrachelus dimidiatus (Champion) causing economic losses to producers. The aim of this study was to assess the behavioral and electrophysiological responses of the weevil to selected semiochemicals emitted by the host plant fruit and to conspecifics. Volatile organic compounds isolated from host plant as β-caryophyllene, (S)-(–)-limonene, hexanal, and nonanal significantly attracted adults of both sexes in behavioral bioassays. Electroantennogram recordings showed largest responses to papayanal and grandlure III + IV released by C. dimidiatus and C. nenuphar, respectively. Our results indicate that behavioral and electroantennographic assays using synthetic compounds from host plant volatiles and insect volatile pheromones produce olfactometry and electroantennographic responses in C. dimidiatus. This is the first report of intraspecific chemical communication in this weevil. We discuss the significance of these responses for the natural behavior in guava orchards and their potential use in a pest management strategy.

The male fruit fly attractants, cue-lure (CL) and raspberry ketone (RK), are important in pest management. These volatile phenylbutanoids occur in daciniphilous Bulbophyllum Thouar (Orchidaceae: Asparagales) orchids, along with zingerone (ZN) and anisyl acetone (AA). While these four compounds attract a similar range of species, their relative attractiveness to multiple species is unknown. We field tested these compounds in two fruit fly speciose locations in north Queensland, Australia (Lockhart and Cairns) for 8 wk. Of 16 species trapped in significant numbers, 14 were trapped with CL and RK, all in significantly greater numbers with CL traps than RK traps (at least in higher population locations). This included the pest species Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) (CL catches ca. 5× > RK), Bactrocera neohumeralis (Hardy) (Diptera: Tephritidae) and Bactrocera bryoniae (Tryon) (Diptera:Tephritidae) (CL catches ca. 3× > RK), and Bactrocera frauenfeldi (Schiner) (Diptera:Tephritidae) (in Cairns—CL catches ca. 1.6× > RK). Seven species were trapped with AA, and all were also caught in CL and RK traps in significantly greater numbers, with the exception of B. frauenfeldi. For this species, catches were not statistically different with CL, RK, and AA in Lockhart, and RK and AA in Cairns. Seven species were trapped with ZN, two at this lure only, and the remainder also with CL or RK but in significantly greater numbers. This is the first quantitative comparison of the relative attractiveness of CL, RK, AA, and ZN against multiple species, and supports the long-held but untested assumption that CL is broadly more attractive lure than RK.

Two species of silver fly, Leucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) (Diptera: Chamaemyiidae), from the Pacific Northwest region of North America have been identified as potential biological control agents of hemlock woolly adelgid (Hemiptera: Adelgidae: Adelges tsugae Annand) in eastern North America.The two predators are collectively synchronized with A. tsugae development.To determine whether adult emergence of the two species of silver fly are also synchronized with one another, we collected adult Leucopis which emerged from A. tsugae-infested western hemlock [Pinaceae: Tsuga heterophylla (Raf.) Sarg.] from four sites in the Pacific Northwest over a 29-d period. Specimens were collected twice daily in the laboratory and identified to species using DNA barcoding. The study found that more adult Leucopis were collected in the evening than the morning. Additionally, the daily emergences of adults over the 29-d sampling period exhibited sinusoidal-like fluctuations of peak abundance of each species, lending evidence to a pattern of temporal partitioning.This pattern could have logistical implications for their use as biological control agents in eastern North America, namely the need to release both species for maximum efficacy in decreasing A. tsugae populations.

Bioindication is a method to assess environmental conditions using indicator organisms. In Colombia, water quality evaluation is mostly performed following the Biological Monitoring Working Party/Colombia method (BMWP/ Col), which uses aquatic macroinvertebrates at the taxonomic family level. Studies on potential bioindicators are important to produce comprehensive information on the requirements of macroinvertebrates and their value for water quality bioindication. We studied the larval ecology of several common genera of Odonata from Colombian freshwater ecosystems and assigned an indicator value to each genus.The physical and chemical water characteristics of 1,022 sites surveyed in Colombia from 2005 to 2016 were analyzed using a principal component analysis (PCA). The relationship between environmental conditions and Odonata genera found was studied using multiple logistic regressions between sample coordinates of the first three axes of the PCA and occurrence of the respective genus. We assigned an indicator value for each genus using the logistic regression and the water quality of samples. The highest indicator values were assigned to genera, which were mainly explained by the PCA axis associated with water quality, showed a high odds ratio to this axis, and were found in ecosystems with excellent water quality.The indicator values suggested for each taxon are, Brechmorhoga Kirby, 1894, 8; Macrothemis Hagen, 1868, 4; Micrathyria Kirby, 1889, 4 (Libellulidae); Progomphus Selys, 1854, 7 (Gomphidae); Acanthagrion Selys, 1876, 4; and Argia Rambur, 1842, 7 (Coenagrionidae). Differences in water quality preferences in genera of the same family suggest that higher taxonomic resolution may allow more detailed environmental assessments.

Abiotic factors can affect plant performance and cause stress, which in turn affects plant–herbivore interactions. The Environmental Stress Hypothesis (ESH) predicts that gall-inducing insect diversity will be greater on host plants that grow in stressful habitats. We tested this hypothesis, considering both historical and ecological scales, using the plant Copaifera langsdorffii Desf. (Fabaceae) as a model because it has a wide geographic distribution and is a super-host of gall-inducing insects. According to the ESH, we predicted that 1) on a historical scale, the diversity of gall-inducing insects will be higher in habitats with greater environmental stress and 2) on an ecological scale, gall-inducing insect diversity will be greater on plants that possess greater levels of foliar sclerophylly. We sampled gall-inducing insects on plants of C. langsdorffii in five sites with different levels of water and soil nutrient availability and separated from each other by a distance of up to 470 km. The composition, richness, and abundance of gall-inducing insects varied among study sites. Plants located in more stressful habitats had higher levels of foliar sclerophylly; but richness and abundance of gall-inducing insects were not affected by host plant sclerophylly. Habitat stress was a good predictor of gall-inducing insect diversity on a regional scale, thus corroborating the first prediction of the ESH. No relationship was found between plant sclerophylly and gall-inducing insect diversity within habitats. Therefore, on a local scale, we did not find support for our second prediction related to the ESH.

Diversifying cropland plant communities is prerequisite to restoring ecosystem functions in agricultural habitats. Cover crops are one such way to improve biodiversity, and broadcasting calcium carbonate-coated (lime) seeds can be a viable method for plant establishment. In addition to improving seed-to-soil contact, calcium carbonate may also reduce arthropod granivory. Here we examine the effect of this seed-coating technology on arthropod granivory for seven cover crop species under field conditions. Carabidae, Gryllidae, and Staphylinidae were the three most frequently collected granivorous taxa in pitfall samples, and Pterostichus permundus and Gryllus pennsylvanicus represented 60.8% of all individual granivores. Cover crop seed damaged was variable among plant species. Among all plant species, the presence of a seed coating significantly reduced granivory by nearly 40% in the 7-d field exposure. Individually, hairy vetch and sorghum × sudan seeds were especially protected by calcium carbonate. No positive correlations were observed between invertebrate groups and the number of seeds consumed. Alternative methods for assessing the functionality of granivorous arthropod communities should be pursued, as activity-density measured from pitfall traps failed to reveal important cover crop seed consumers. Protection of cover crop seeds from granivory through a calcium carbonate coating may allow producers to adjust seeding rates and save on costs, increasing the rate of adoption for this conservation practice.

Spotted lanternfly, Lycorma delicatula (White), is an invasive Asian insect that was initially found in Berks County, Pennsylvania, in 2014. As of early 2020, this pest had been found in five more eastern states and it is expected to continue to expand its geographical range. Lycorma delicatula is highly polyphagous but seems to prefer tree-of-heaven, Ailanthus altissima. However, grape growers in Pennsylvania have reported significant damage and loss of vines caused by L. delicatula adults. In fall 2018, two fungal entomopathogens (Beauveria bassiana and Batkoa major) drove localized collapses in L. delicatula populations in Berks County, Pennsylvania. In 2019, we tested applications of a commercialized mycoinsecticide based on B. bassiana strain GHA on L. delicatula populations in a public park in southeastern Pennsylvania. A single application of B. bassiana reduced fourth instar nymphs by 48% after 14 d. Applications of B. bassiana to L. delicatula adults in the same park resulted in 43% mortality after 14 d. Beauveria bassiana spores remained viable on foliage for 5–7 d after spraying. We also conducted semi-field bioassays with B. bassiana GHA (formulated as BoteGHA and Aprehend) and another mycoinsecticide containing Isaria fumosorosea Apopka Strain 97 against L. delicatula adults feeding on potted grapes. All the mycoinsecticides killed ≥90% of adults after 9 d using direct applications. Aprehend killed 99% of adults after 9 d with exposure to residues on sprayed grapes. These data show that fungal entomopathogens can help to suppress populations of L. delicatula in agroecosystems and natural areas.

In organic agronomic cropping systems, the use of synthetic insecticides and transgenic varieties are prohibited and producers rely mainly on biological control, tillage, crop rotation, and other cultural practices to manage pests. We measured damage to organic corn (Zea mays L.) from multiple invertebrate pests, including slugs (Gastropoda: Mollusca), European corn borer (Ostrinia nubilalis Hübner), corn earworm (Helicoverpa zea Boddie), and fall armyworm (Spodoptera frugiperda Smith), early and late in the growing season in four cropping systems that varied in tillage frequency and intensity and in winter cover crop species. Specific management tactics included two cover crop mixtures preceding corn, the use of a roller-crimper or tillage to terminate cover crops preceding corn, and the establishment of interseeded cover crops after corn emergence. Prevalence of early-season damage was high, but severity of damage was very low and unrelated to corn yield. The proportion of corn plants affected by chewing pests early in the season was lower in plots in which tillage compared to a roller-crimper was used to terminate cover crops. Cropping system did not affect the numbers of late-season caterpillar pests or corn yield. Predation by natural enemies appeared to effectively maintain damage from chewing pests below yield-damaging levels. These results support the inclusion of winter and interseeded cover crops in organic agronomic crop rotations to gain environmental benefits without increasing risks of damage by insect pests.

A number of soybean varieties traditionally bred for resistance to various soybean arthropod pests have been identified as resistant to Megacopta cribraria (F.) (Hemiptera: Plataspidae). However, the mechanisms of host-plant resistance (HPR) in this system are not understood. The goal of this study was to identify the mechanisms of resistance by examining the role of plant volatile organic compounds (VOCs) and free amino acids (FAAs) among 16 soybean varieties. Choice and no-choice cage experiments identified several soybean varieties that demonstrated antixenosis as well as antibiosis. However, resistance varied over time in certain soybean varieties, such as N02-7002 and PI567352B. Mean nymph number from choice experiments had positive correlations with the FAAs asparagine, tryptophan, alanine, phenylanaline, and serine; negative correlation with leucine and threonine. Four plant volatiles, hexanal, 2-pentylfuran, beta-cyclocitral, and cis-9-hexadecenal, were positively correlated with subsequent nymph development, whereas n-hexadecenoic acid was negatively correlated with nymph number only, in adult choice cage experiments. This study contributes to understanding the mechanisms of HPR through associations with plant VOCs and FAAs in relation to M. cribraria development and provides useful knowledge for developing soybean varieties for M. cribraria management.

Perilla, Perilla frutescens (L.) Britton var. crispa (Thunb.) H. Deane, is traditionally cultivated as an edible/medicinal crop in East Asia. Its essential oil contains many bioactive compounds that are expected to have high pharmacological functionality, as well as antimicrobial and insecticidal activity. Spider mites are a major pest group for perilla cultivation. The two-spotted spider mite, Tetranychus urticae Koch, possesses divergent detoxification enzymes and has developed resistance against most acaricides. The essential oil content of perilla halves from the preflowering phase to the flowering phase, and ultraviolet (UV)-B radiation generally increases defense compounds. To clarify the effects of this change in essential oil content and the effects of UV-B pretreatment, we investigated the developmental success and egg production of T. urticae on leaves from the preflowering and flowering phases cultivated with and without nighttime UV-B irradiation. Both the parameters significantly increased on leaves from the flowering phase in comparison with that from the preflowering phase, suggesting that constitutively produced essential oil provided protection against mite pests in a growth phase-specific manner. The defense system also extended the developmental period of mites on red perilla leaves, but not on green perilla leaves, in preflowering phase. Although egg production was lower on red perilla leaves pretreated with UV-B, no negative effects were caused on the developmental success and duration on red and green perilla and the egg production on green perilla by UV-B pretreatment. Our findings reveal a significant impact of investment allocation of perilla plants and a small contribution of UV-B irradiation to the plant defense system.

Insect diapause is a state of arrested development persisting when conditions are favorable for growth. Prolonged diapause, which occurs when insects remain in diapause for multiple years, is uncommon. Mormon crickets Anabrus simplex Haldane, a katydid and pest of rangeland forage and crops, were thought to be biennial in the Bighorn Mountains of Wyoming, but they are able to prolong diapause in the egg stage for multiple years. To test whether parental photoperiod serves as a cue to prolong diapause, mating pairs from the Bighorn Mountains were set in the same daily temperature and humidity profiles with 20 pairs on short daylength (12:12 [L:D] h) and 20 on long daylength (15:9 [L:D] h). Almost every parental pair had some undeveloped eggs after two warm periods. Females in short daylength were not more likely to have eggs with a biennial life cycle, but they were more likely than those in long daylength to lay eggs with multi-annual life cycles. Parents on short daylength were more likely to lay inviable eggs. Other fitness measures, such as hatchling mass, nymphal survivorship, and adult mass were not different between parental treatments. Diapause termination distributed over multiple years probably constitutes a bet-hedging strategy in an unpredictable environment.

Graphical Abstract

Insect microbiota may play a wide range of roles in host physiology. Among others, microbiota can be involved in diet processing or protection against pathogens, both of which are potentially important in bryophagous (moss-feeding) insects, which survive on extreme diets and live in the stable environment of moss clumps suitable for the growth of fungi and bacteria. We treated Cytilus sericeus (Forster, 1771) (Coleoptera: Byrrhidae) as a model organism with bactericides and fungicides to test the effect of bacterial and fungal removal on egg hatching and larval development. Furthermore, we supplied larvae with adult feces to determine whether feces is a source of beneficial microbiota or pathogens. Bactericides had a positive effect, but fungicides had a negative effect on beetle fitness, both of which manifested during egg hatching. The feces did not play a positive role. Our conclusions indicate the presence of beneficial fungal microbiota associated with eggs but not transmitted through feces. Based on preliminary cultivation and fungicide tests, Fusarium or Penicillium may be important for suppressing pathogens, but their exact role needs to be further studied.

Diapause induction in multivoltine insects is an ecophysiological event that is generally triggered by seasonal cues such as photoperiod and temperature. The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), feeds on various Poaceae grasses and produces several generations a year. Previous studies have shown that adults produce diapause and nondiapause eggs under short-day and long-day conditions, respectively. However, there is a distinct midsummer peak in diapause incidence before an autumnal increase in diapause incidence in the field, which cannot be explained by the laboratory results.The present study was performed to examine the environmental factors affecting the diapause incidence in mid-summer and the adaptive significance of this phenomenon. Seasonal trends in diapause incidence differed significantly among three sites located 150–400 m apart from each other and with different host plants. The suitability of host plants differs depending on species and seasonally. Therefore, the microhabitat difference in diapause trend is believed to be due to the difference in host plants. When field-collected female adults laying diapause eggs in late June were fed a seasonally deteriorating host (the orange foxtail, Alopecurus aequalis Sobol. [Poales: Poaceae]), they kept laying diapause eggs, whereas when fed a suitable host (the wheat, Triticum aestivum L. [Poales: Poaceae]) for 5 d, they changed oviposition mode to lay nondiapause eggs.These results indicate that host-plant suitability affects the oviposition mode of T. caelestialium. Diapause-egg oviposition in mid-summer in T. caelestialium has adaptive significance as a bet-hedging strategy against unpredictable dietary conditions.

Terrestrial insects face the risk of desiccation owing to their small size and high surface area to volume ratios. Insect eggs adhered to exposed substrates are especially prone to extremes in temperature and available moisture.The potential of butterfly egg clusters to withstand desiccation in saturated and unsaturated atmospheres was investigated in this study. Butterflies in the genus Neophasia (Lepidoptera: Pieridae) lay their eggs along live pine needles and they must survive long intervals without available liquid water while overwintering. After 2 d in a desiccating environment, groups of Neophasia terlooii Behr eggs were exposed to several different humidified chambers for 8 d at 5°C. Group masses were monitored over time and the change in mass was compared to the pre-desiccation mass. Changes in mass were minimal, ranging from a 3% increase in the saturated chamber (100% RH) to a 2% decrease in the driest chamber (<10% RH). Ambient humidity was recorded from among the pine needles of a live tree branch in the natural habitat for 2 wk at the start of the overwintering period. Daytime relative humidity among the pine needles dropped as low as 14.5% but rose as high as 92% at night. In the absence of precipitation, N. terlooii eggs can remain within 2% of their starting weight for 10 d at a constant RH of <10% at 5°C.The mechanism for avoiding desiccation and the physical properties of the egg coating are discussed in the context of life in an arid environment.

In three Dutch populations of the native small hogweed (Heracleum sphondylium L. [Apiales: Apiaceae]), and one of the invasive giant hogweed (H. mantegazzianum Sommeier & Levier [Apiales: Apiaceae]), interactions between a specialist herbivore, the parsnip webworm (Depressaria radiella), and its associated parasitoids were compared during a single growing season. We found host plant species-related differences in the abundance of moth pupae, the specialist polyembryonic endoparasitoid, Copidosoma sosares, the specialist pupal parasitoid, Barichneumon heracliana, and a potential hyperparasitoid of C. sosares, Tyndaricus scaurus Walker (Hymenoptera: Encyrtidae). Adult D. radiella body mass was similar across the three small hogweed populations, but moths and their pupal parasitoid B. heracliana were smaller when developing on giant than on small hogweeds where the two plants grew in the same locality (Heteren). Mixed-sex and all-male broods of C. sosares were generally bigger than all-female broods. Furthermore, adult female C. sosares were larger than males and adult female mass differed among the three small hogweed populations. The frequency of pupal parasitism and hyperparasitism also varied in the different H. sphondylium populations.These results show that short-term (intra-seasonal) effects of plant population on multitrophic insects are variable among different species in a tightly linked food chain.

Erythroneura sudra is a leafhopper occurring in northern China, which causes significant damage to fruit. The relationships between E. sudra and five fruit tree species (Rosaceae) were studied for 3 yr.The highest relative density of E. sudra was recorded on leaves of Amygdalus persica L. and Cerasus pseudocerasus Lindl. Likewise, it had the highest survival rate and shortest developmental time when it fed on these two plants species, indicating that they were the most preferred by E. sudra than the other plant species. The relative density and growth performance of E. sudra were negatively correlated with the levels of tannins and flavonoids in the leaves of the host species. Both plant species had relatively lower flavonoids and tannins, and this may have contributed to the enhanced survival and population growth of E. sudra. These results can guide the development of improved management strategies for this pest.

The ability to adapt to a novel host plant may vary among insect populations with different genetic histories, and colonization of a marginal host may be facilitated by genetic admixture of disparate populations. We assembled populations of the seed beetle, Callosobruchus maculatus (F.), from four continents, and compared their ability to infest two hosts, lentil and pea. We also formed two cross-continent hybrids (Africa × N.A. and Africa × S.A.). In pre-selection assays, survival was only ∼3% in lentil and ∼40% in pea. For three replicate populations per line, colonization success on lentil was measured as cumulative exit holes after 75–175 d. On pea, we estimated the change in larval survival after five generations of selection. Females in all lines laid few eggs on lentil, and survival of F₁ larvae was uniformly <5%. Subsequently, however, the lines diverged considerably in population growth. Performance on lentil was highest in the Africa × N.A. hybrid, which produced far more adults (mean > 11,000) than either parental line. At the other extreme, Asian populations on lentil appeared to have gone extinct. The Africa × N.A. line also exhibited the highest survival on pea, and again performed better than either parent line. However, no line displayed a rapid increase in survival on pea, as is sometimes observed on lentil. Our results demonstrate that geographic populations can vary substantially in their responses to the same novel resource. In addition, genetic admixtures (potentially caused by long-distance transport of infested seeds) may facilitate colonization of an initially poor host.

In the context of global pollinator decline, little is known about the protection status and ecology of many species. This lack of knowledge is particularly important for Mediterranean protected areas that harbor diverse pollinator communities and are subject to considerable anthropogenic pressures. Calanques National Park (85 km²), which is located near Marseille (France), is dominated by Mediterranean low-vegetation habitats, such as phrygana and scrublands. These habitats offer favorable conditions for pollinator species due to the important amount of floral resources. Within a 10-yr period, we recorded bee (Hymenoptera: Apoidea: Anthophila), hover fly (Diptera: Syrphidae), and bee fly (Diptera: Bombyliidae) species and their interactions with the local flora through 10 field campaigns. We caught 250 pollinator species, including 192 bees, 38 hover flies, and 20 bee flies, for a total of 2,770 specimens. We recorded seven threatened bees (six near threatened and one endangered). Among the bee species, 47.9% were below-ground nesting species, and 54.7% were generalist species. Analysis of the pollination network showed that generalist and specialist pollinators do not share the same floral resources. The Cistaceae plant family (Malvales: Cistaceae) acted as a central node in the plant–pollinator network, interacting with 52 different pollinator species, which shows the importance of large open flowers that could be easily visited by both short and long-tongued pollinators in Mediterranean habitats. The occurrence of pollinator species and their ecological traits should strongly contribute to reinforcing the available information to provide or ameliorate the conservation statuses determined by IUCN Red List.

Habitat disturbance has been found to facilitate the introduction of a wide range of species, including the red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae: Myrmicinae). Despite the link between S. invicta colonization and disturbance, little is known about how different intensities or types of disturbance might impact S. invicta populations. In this study, we used S. invicta populations in cattle pastures to understand how variation in disturbance type and frequency correlates with the density of S. invicta mounds. In total, 56 plots were surveyed for mound abundance during both the wet and dry seasons on a subtropical south Florida ranch. Explanatory variables were grouped into five categories based on disturbance type: 1) historic pasture conversion; 2) modern pasture management (mowing, dragging, chopping, or aerating); 3) grazing intensity (a measure vegetation height and dung pat abundance); 4) distance to human-made and natural localized disturbance (roads, ditches, and wetlands); and 5) abiotic conditions (soil temperature, soil moisture). Overall, the average number of mounds per plot was not significantly different between seasons, but was significantly higher in intensive pastures, which are converted to nonnative forage grasses than in seminative pastures during the dry season.Time since soil disturbance (aeration and chopping of pasture) was a significant predictor of S. invicta densities in both dry and wet seasons, with an increase in time since disturbance being associated with higher mound densities. Other forms of pasture management that did not disturb the soil, such as dragging and mowing, as well as distance to localized disturbances (wetlands, roads, and ditches) were not found to have a significant correlation in either season.

By completely censusing a 1 ha forest dynamics plot it was possible to identify the variables (spider mass, size, sex and tree species, size, and bark roughness) that influenced the spatial distribution of adult Drapetisca alterandaChamberlin 1909 (Araneae: Linyphiidae), a sheet web spider that specializes in lower tree trunks in North American forests. To account for spatial autocorrelation, a conditional autoregressive random effect was included in the zero-inflated Poisson generalized linear mixed model. Parameters estimated were produced by Bayesian inference with vague prior probability distributions and the best of 16 models were selected using Watanabe-Akaike Information Criterion. The best model showed that larger diameter trees located at higher plot elevations were more likely to have D. alteranda present. Smooth bark tree species such as paper birch and American basswood tended to have the most spiders while rough bark species had the least. The relationship between tree diameter and D. alteranda abundance also varied by tree species. Paper birch and quaking aspen tend to produce a greater slope compared to the other species, indicating that as these trees get larger, the abundance of D. alteranda increases at a higher rate than on other tree species. Spider sex and size were not associated with height on the trunk or tree species selection, nor were they associated with microhabitats such as bark furrow depth. Landscape-level factors largely predict D. alteranda abundance and distribution, suggesting that spatial autocorrelation should be considered when modeling the abundance of even small organisms, such as spiders.

Understanding factors that affect the population dynamics of insect pest species is key for developing integrated pest management strategies in agroecosystems. Most insect pest populations are strongly regulated by abiotic factors such as temperature and precipitation, and assessing relationships between abiotic conditions and pest dynamics can aid decision-making. However, many pests are also managed with insecticides, which can confound relationships between abiotic factors and pest dynamics. Here we used data from a regional monitoring network in the Pacific Northwest United States to explore effects of abiotic factors on populations of an intensively managed potato pest, the potato psyllid (Bactericera cockerelli Šulc), which can vector Candidatus Liberibacter psyllaurus, a bacterial pathogen of potatoes. We assessed effects of temperature on psyllid populations, and show psyllid population growth followed predictable patterns within each year, but there was considerable variation across years in psyllid abundance. Examination of seasonal weather patterns suggested that in 2017, when psyllid populations were less abundant by several orders of magnitude than other years, a particularly long and cold period of winter weather may have harmed overwintering populations and limited population growth. The rate of degree-day accumulation over time, as well as total degree-day accumulation also affected trap catch abundance, likely by mediating the number of psyllid generations per season. Our findings indicate that growers can reliably infer the potential magnitude of risk from potato psyllids using monitoring data, date of first detection, seasonal weather patterns, and population size early in the growing season.

We present the results of a 5-yr field study on colony dynamics and plant community associations of Owyhee harvester ants, Pogonomyrmex salinus (Olsen), in sagebrush-steppe habitat in southwestern Idaho. Over a 5-yr period, the total number of ant colonies across 16 sites increased from 843 to 878 (4.15%) as a result of 315 colony deaths and 350 colony initiations. Up to 7.1% of colony initiations may have been instances of nest relocation. Colonies had a higher rate of failure in their first year than in subsequent years (12.4 vs 4.6–8.4% over the next 3 yr). Of the 11 sites analyzed for colony dispersion, one was significantly clumped and the others did not differ from random. Population density in the final year of study ranged from 0.1 to 62.9 colonies/ha and was best described by an inverse relationship with sagebrush cover and positive relationship with coverage of non-Bromus (non-cheatgrass) understory vegetation. We interpret these results both in terms of 1) food resources—harvester ants avoid cheatgrass seeds in their diet, preferring instead small-seeded grasses and forbs, and 2) habitat structure—harvester ants prefer nesting in open areas where the ground is exposed to sun and they can clear vegetation from the vicinity of their nests. Given the habitat associations we report, the transition from sagebrush-dominated habitat to open grasslands that is occurring rapidly throughout much of the western United States may prove costly to native plant species whose seeds are readily consumed by harvester ants.

Developing a lifelong marking method for Lycorma delicatula (White, 1845) is crucial to investigate ecological processes. Here we validate a marking method using stable isotope enrichment (¹⁵N) of host plants to track spotted lanternfly (SLF), an invasive species causing economic damage on grapes, hardwood forest and landscape tree species. To validate this method, we first determined the isotope dosage to be sprayed on the host plants and subsequently detected in SLF. Second, we examined whether ¹⁵N mark remains detectable from the nymphal to adult stage. We demonstrated that two stable isotope dosages applied to the host plants were assimilated by the insect and equally detectable in the exoskeleton, wings, and mature eggs ready to be oviposited. This safe and reliable method can be used to examine fundamental processes of the biology and ecology of SLF that range from dietary resources and resource allocation to food-web structure and dispersal patterns.