Distribution and phenology of monarch butterfly larvae and their milkweed hosts in the South Central US

South Central US milkweeds (Asclepias) are critical adult nectar and larval food resources for producing the first spring and last summer/fall generations of declining eastern migratory monarch butterflies (Danaus plexippus). This study addresses multiple gaps in assessment of monarch conservation priorities for the South Central US through analyses of monarch larval host selectivity, phenology, and spatial density, as well as the phenology, niche modeled distribution, and land cover selectivity of important milkweed hosts. Results are synthesized to estimate seasonal milkweed resource areas. About 70% of monarch larval activity occurred from mid-March to mid-July (early season) and 30% from mid-August to late November (late season). Twenty-six wild milkweed (Apocynaceae) hosts were mapped, including four new records for North America. Important hosts included Asclepias a. ssp. capricornu, A. viridis, and A. oenotheroides, that were utilized more frequently during early season, and Asclepias latifolia, utilized more frequently during late season. Landscape host selectivity was positive for A. viridis and A. a. ssp. capricornu in late and early seasons, respectively, and negative for A. oenotheroides in late season. Milkweed land cover selectivity was positive for Developed-Open Space and Grassland Herbaceous, and negative for Cultivated Crops and Shrub/Scrub. Seasonal milkweed resource areas and larval spatial densities resolved interior and coastal corridors providing functional connectivity for monarch spring and fall migrations. A potential gap in milkweed land cover benefit was identified in South Texas. The novel merging of milkweed niche models with larval phenology, host selectivity, milkweed phenology, and land cover selectivity informs conservation assessment.

Ecological interactions: Patterns of host utilization by tropical butterflies

Structural complexity of ecological networks facilitate the functional robustness of natural ecosystems. Threatened by the human actions such as habitat destruction and climate change, species may be more or less prone to ecological perturbations depending on the nature of their interactions. We examined the host network of tropical butterflies from the Indian region to see their level of interconnectedness. We manually curated larval host utilization data for 1053 butterflies of India. About 98.8% of species that occur pan-India and 90.6% of species exclusive to the Western Ghats had known hosts whereas it was only 25.9% for species exclusive to north-east India. There were 2589 unique butterfly-host interactions comprising 519 butterfly species and their 1091 known hosts. However, nearly 30% of the species had only single hosts. The Fabaceae and Poaceae were the key host families that accounted for 32.8% of the interactions. There were clear host preferences and monocots hosted disproportionately more butterfly species and interactions. Vanessa cardui had at least 39 known hosts while Ochlandra travancorica supported 19 butterfly species. There were 2693 species-pairs and 4226 interactions among 469 butterflies due to shared hosts. Many butterfly species that have relatively few/unique hosts might be vulnerable in the context of habitat destruction and climate change. This work has great relevance to the ecology and conservation of butterflies in India.

Diversity of moths from the urban set-up of Valmiki Nagar, Chennai, India

A study was conducted at Valmiki Nagar, Chennai, Tamil Nadu, India to explore its moth diversity from December 2018 to May 2021. This manuscript presents a partial checklist of moths from Valmiki Nagar. Four locations around the colony were studied to record the moth fauna. The study sites were surveyed twice a month using a mercury vapour lamp along with a white sheet, along with over 100 visits at night. Diurnal surveys were conducted bimonthly to observe larval host plants and day flying moths. A total of 135 species were recorded from the study area, belonging to nine superfamilies. The most diverse family of moths recorded was family Erebidae, with 39% of moths recorded in the study belonging to this family, followed by Crambidae (30%), Geometridae (8%), and other families constituting the rest. The moth diversity in the month of July was seen to be the highest. Along with this study, future studies on similar lines will help in documenting the moth diversity of Chennai.

Insect Pest Management of Vegetables in Pocket Areas of Modi Rural Municipality, Parbat

Modi Rural Municipality is one of the commercial vegetable pocket areas under temperate climate. A study was carried out during July 2021 in three vegetable growing areas: Tilahar, Deupur and Bajung of Modi Rural Municipality. A total number of nine quadrates (10×10) m2 were laid, including three replicating quadrates in each area with 500m differences from each quadrates in the sampling site. Overall, 18 farmers were interviewed to collect information about vegetables grown, insect pests that affected vegetables and their management practices. The total number of 24 insect pests were recorded belonging to five orders from 14 vegetable crops. Greater Sorensen's similarity index of insects was recorded in Tilahar and Deupur (ß=0.52) because there was similarity in environment, habitats, larval host plants and visiting plants of insects. Lower Sorensen's similarity index (ß=0.25) was recorded in Deupur and Bajung as there was less similarity in environment, habitats, larval host plants and visiting plants of insects. Insect pests and diseases on vegetables were the major problems in the study areas. The use of chemical insecticides was the means to control adopted by most of farmers while a few of them used other control methods. Insecticides on pests were applied considering fewer precautions. The study clearly indicated that the farmer’s knowledge towards Integrated Pest Management (IPM) was null and thus necessary action should be taken by concerned agencies to increase rate of vegetable production, avoid the heavy use of chemicals and allied consequences.

MORPHOLOGY AND MOLECULAR IDENTIFICATION OF THE LARVAL STAGE OF TWO SPECIES FROM THE GENUS CHRYSOBOTHRIS ESCHSCHOLTZ, 1829 (COLEOPTERA, BUPRESTIDAE)

The genus of Chrysobothris Eschscholtz, 1829 is one of the most diverse and widespread genera of the family Buprestidae of some 700 described species distributed throughout the world. In Iraq, particularly in the Kurdistan region, about 4 species had been recorded so far, many of these species are sympatric, share larval host plants, and are difficult to reliably separate morphologically. The current study investigates species limits and relationships among the recognized species occurring within the Erbil Province; mitochondrial cytochrome C oxidase (COX I) molecular analysis confirmed the monophyly of two Chrysobothris species, Ch. affinis (Fabricius, 1794) and Ch. chrysostigma (Linnaeus, 1758). Implications of the resultant larval morphology and molecular techniques are discussed. Diagnostic characteristics that are depended to identifying the species within Chrysobothris in larval stage were illustrated and then compared with the molecular data.

The price of defence: toxins, visual signals and oxidative state in an aposematic butterfly

In a variety of aposematic species, the conspicuousness of an individual's warning signal and the quantity of its chemical defence are positively correlated. This apparent honest signalling in aposematism is predicted by resource competition models which assume that the production and maintenance of aposematic defences compete for access to antioxidant molecules that have dual functions as pigments directly responsible for colouration and in protecting against oxidative lipid damage. Here we study a model aposematic system - the monarch butterfly (Danaus plexippus) and make use of the variable phytochemistry of its larval host-plant, milkweeds (Asclepiadaceae), to manipulate the concentration of sequestered cardenolides. We test two fundamental assumptions of resource competition models: that (1) the possession of secondary defences is associated with costs in the form of oxidative lipid damage and reduced antioxidant defences; and (2) that oxidative damage or decreases in antioxidant defences can reduce the capacity of individuals to produce aposematic displays. Monarch caterpillars that sequestered the highest concentrations of cardenolides exhibited higher levels of oxidative lipid damage as adults. The relationship between warning signals, cardenolide concentrations and oxidative damage differed between the sexes. In male monarchs conspicuousness was explained by an interaction between oxidative damage and sequestration: as males sequester more cardenolides, those with high levels of oxidative damage become less conspicuous, while those that sequester lower levels of cardenolides equally invest in conspicuous with increasing oxidative damage. There was no significant effect of oxidative damage or concentration of sequestered cardenolides on female conspicuousness. Our results demonstrate physiological linkage between the production of coloration and protection from autotoxicity, that warning signals can be honest indicators of defensive capability, and that the relationships are different between the sexes.

Echoentomography for Assessing Braconid Parasitization on Soft-Bodied Tephritid Hosts

Entomological approaches currently available for assessing host parasitization require dissection, polymerase chain reaction (PCR), or waiting for adult emergence. The first two methods are relatively fast but destructive, whereas the third one allows the emergence of the parasitoid but it is time consuming. In this framework, new diagnostic imaging tools may contribute to solve the lack of an accurate, rapid, and non-invasive approach to evaluate the parasitization of soft-bodied insects by their endoparasitoids. In this study, ultra-high frequency ultrasound (UHFUS) technology, which is currently used in medical and preclinical fields, was adopted to assess the parasitization of the invasive polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), testing 2nd and 3rd instar larvae. Parasitization assays were carried out with the solitary koinobiont endophagous parasitoid Psyttalia concolor (Hymenoptera: Braconidae: Opiinae). The efficacy of UHFUS-based echoentomography was compared with the classical method of dissecting the larval host under a stereomicroscope. Our results showed that the UHFUS diagnostic capability was statistically comparable with that of dissection, both on C. capitata 2nd and 3rd larvae. Overall, UHFUS-based echoentomography may be further considered as a fast, non-invasive, and effective approach to evaluate the parasitoid’s ability to successfully oviposit in soft-bodied hosts.

Butterfly declines in protected areas of Illinois: Assessing the influence of two decades of climate and landscape change

Despite increasing concern regarding broad-scale declines in insects, there are few published long-term, systematic butterfly surveys in North America, and fewer still that have incorporated the influence of changing climate and landscape variables. In this study, we analyzed 20 years of citizen science data at seven consistently monitored protected areas in Illinois, U.S.A. We used mixed models and PERMANOVA to evaluate trends in butterfly abundance, richness, and composition while also evaluating the effects of temperature and land use. Overall butterfly richness, but not abundance, increased in warmer years. Surprisingly, richness also was positively related to percent impervious surface (at the 2 km radius scale), highlighting the conservation value of protected areas in urban landscapes (or alternately, the potential negative aspects of agriculture). Precipitation had a significant and variable influence through time on overall butterfly abundance and abundance of resident species, larval host plant specialists, and univoltine species. Importantly, models incorporating the influence of changing temperature, precipitation, and impervious surface indicated a significant overall decline in both butterfly abundance and species richness, with an estimated abundance decrease of 3.8%/year and richness decrease of 1.6%/year (52.5% and 27.1% cumulatively from 1999 to 2018). Abundance and richness declines were also noted across all investigated functional groups except non-resident (migratory) species. Butterfly community composition changed through time, but we did not find evidence of systematic biotic homogenization, perhaps because declines were occurring in nearly all functional groups. Finally, at the site-level, declines in either richness or abundance occurred at five of seven locations, with only the two largest locations (>300 Ha) not exhibiting declines. Our results mirror those of other long-term butterfly studies predominantly in Europe and North America that have found associations of butterflies with climate variables and general declines in butterfly richness and abundance.

A demographic and ecological study of an Italian population of Polyommatus ripartii: the ESU Polyommatus exuberans

Polyommatus exuberans is an evolutionarily significant unit (ESU) of the lycaenid butterfly Polyommatus ripartii. This ESU is known to survive at only two sites in the Susa Valley (NW Italy). Lack of correct management, reforestation and frequent wildfires severely threaten this ESU (listed as endangered species in the most recent IUCN Italian Red List). Although the taxonomic rank of this taxon is still debated, current threats could cause extinction of its two remaining populations before its taxonomic rank and its ecology are clarified. We collected data for the first time on this population at the small site of Mompantero (ab. 10 ha). We used butterfly GPS-positioning and the mark-release-recapture (MRR)-method to estimate its population size (269 individuals), sex-ratio (1.36 M/F), lifespan (4.76 days), density (47/ha) and mobility (median 153 and 33 m for males and females, respectively). Both sexes are equally catchable. Catchability increases around midday and decreases during overcast weather. While the size and density of this small population are comparable to those of other endemic Polyommatus species (such as P. humedasae and P. gennargenti), scarce mobility makes its populations isolated and even more seriously threatened. Implications for insect conservation We suggest that implementing an active management plan, including mowing before July and/or in autumn, and supporting ant diversity, is of immediate importance. Management should be extended to road verges, where the larval host plant (Onobrychis sp.) is abundant, and would thus also serve as corridors to favour dispersion between sites. Our research is the first study to investigate this taxon, thus shedding some light on the ecological and biological aspects that are crucial for long-term survival.