Entomofauna resource distribution associated with pig cadavers in Bogotá DC

A cadaver represents a temporal energy‐loaded resource, which provides arthropods with food, protection and a place in which to find a mate. Insects are usually the first organisms to discover and colonize a cadaver; as decomposition progresses, insects colonize cadavers in a predictable sequence. This work aimed to establish cadaverous entomofauna relationships with regard to stages of decomposition and environmental conditions using multiple correspondence analysis and thereby to identify the way in which insects distribute a perishable and changing resource. Entomofauna were thus collected in a semi‐rural area near Bogotá from the cadavers of three pigs (Sus scrofa L.) which had been shot. Environmental variables were recorded for each sampling. Multiple correspondence analyses were carried out for adult forms belonging to Diptera and Coleoptera families and stages of decomposition, and for Diptera and Coleoptera adult forms and environmental conditions. Stages of decomposition were a primary determining factor for structuring four guilds of entomofauna. However, environmental conditions influenced insect activity and were therefore a relevant factor in the structure of the entomofauna community. The results showed that the insects' distribution of available resources was related to changes in the stage of decomposition.     

The long-distance migration of Nilaparvata lugens (Stål) (Delphacidae) in China: radar observations of mass return flight in the autumn

Abstract.

• 1 A case study is presented of the autumn migration of the brown planthopper, Nilaparvata lugens (Stål), in the area of Nanjing in the People's Republic of China. The study was made using a high frequency (8 mm wavelength) radar and a net suspended from a kytoon.
• 2 The observations confirmed that long-distance return migrations occur in China in mid and late September, with N.lugens being carried on the prevailing north-easterly wind towards the autumn infestation and overwintering areas of the species.
• 3 After mass take-off in the late afternoon or at dusk, the migrants flew for several hours during the evening, often in a dense layer which formed at heights between about 400 and 1000m above ground. These layers often had well-defined ceilings corresponding to an air temperature of about 16°C. The migration height was above the top of the surface temperature inversion, i.e. the migrants did not fly at the height of the warmest air.
• 4 The dense layer concentrations overflying the radar were backtracked to source areas up to 240 km away in the north-east of Jiangsu Province. Planthoppers observed emigrating from the Nanjing area would reach areas in south Anhui Province or north Jiangxi Province if they flew for 12 h.
• 5 There was a second period of mass take-off at dawn. Insect layers sometimes formed but did not last longer than 1–2h.
• 6 The present results were strikingly different from those previously observed in the dry season in the Philippines, where migratory flight durations were largely confined to periods of about 30min at dusk and dawn.
• 7 Our observations are discussed in relation to the equator-wards return migrations undertaken in autumn by other insect species, and the importance of these migrations for the maintenance of long-flying genotypes in the overwintering populations is considered.

     

Quantitative staging of embryonic development of the tobacco hawkmoth,Manduca sexta

Summary A complete timetable of embryonic development of the tobacco hawkmoth,Manduca sexta (Lepidoptera: Sphingidae), is presented. Using living embryos, 20 developmental stages from oviposition to hatching are described with respect to their morphological and physiological maturation. This staging series provides a simple method to identify the stage ofManduca development during all phases of embryogenesis.     

Downwind migration of the African army worm moth, Spodoptera exempta, studied by mark-and-capture and by radar

Abstract. 1. About 166,000 African armyworm moths, Spodoptera exempta (Walk.), were marked at an emergence site near Nairobi when they fed at night on trees baited with dyed molasses.
2. Six marked moths were captured in pheromone traps, including one at 90 km after flying for only one night, and another at 147 km.
3. Moth flight trajectories deduced from radar and from marking showed that migration was downwind.
4. During migration, moths become dispersed; hence the high densities that lead to outbreaks must be produced by concentration.
5. Some moths were ready to mate on the same night they completed their long-distance flight.     

Two human cases associated with forensic insects in Riyadh,Saudi Arabia

In Riyadh, Saudi Arabia, we are reporting two cases of natural death. The two bodies showed different types of habitat, insect colonization and decomposition stage. The first case was about the body of a 65-years-old male, with mummification of the clothed body was found in an outdoor habitat. Different life stages of Dermestes maculatus DeGeer (Coleoptera: Dermestidae were gathered from the cadaver, and due to the advanced degree of decomposition, the PMImin was estimated to be 3 months. The second body belonging to a 40-years-old male, was found in a semi-closed apartment (indoor habitat), and the body was at the end of the bloated decomposition stage. In this case, Musca domestica L. (Diptera: Muscidae) larvae were collected, and the PMImin was estimated to be 4 days. The limited insect activity for the two bodies caused by the advanced decomposition stage in the first case and indoor environment in the second. Average temperatures of (23.3 ± 1.6) °C for the first body and (27.5 ± 1.7) °C2 for the second body. Habitat was the key factor to attract insects to the two cadavers. This study stressed that, for accurate estimates of time since death, knowledge of the impact of different variables on insects found over and around the carrion is essential.     

Winds at departure shape seasonal patterns of nocturnal bird migration over the North Sea

On their migratory journeys, terrestrial birds can come across large inhospitable areas with limited opportunities to rest and refuel. Flight over these areas poses a risk especially when wind conditions en route are adverse, in which case inhospitable areas can act as an ecological barrier for terrestrial migrants. Thus, within the east-Atlantic flyway, the North Sea can function as an ecological barrier. The main aim of this study was to shed light on seasonal patterns of bird migration in the southern North Sea and determine whether departure decisions on nights of intense migration were related to increased wind assistance. We measured migration characteristics with a radar that was located 18 km off the NW Dutch coast and used simulation models to infer potential departure locations of birds on nights with intense nocturnal bird migration. We calculated headings, track directions, airspeeds, groundspeeds on weak and intense migration nights in both seasons and compared speeds between seasons. Moreover, we tested if departure decisions on intense migration nights were associated with supportive winds. Our results reveal that on the intense migration nights in spring, the mean heading was towards E, and birds departed predominantly from the UK. On intense migration nights in autumn, the majority of birds departed from Denmark, Germany and north of the Netherlands with the mean heading towards SW. Prevailing winds from WSW at departure were supportive of a direct crossing of the North Sea in spring. However, in autumn winds were generally not supportive, which is why many birds exploited positive wind assistance which occurred on intense migration nights. This implies that the seasonal wind regimes over the North Sea alter its migratory dynamics which is reflected in headings, timing and intensity of migration.     

Survivorship and Spatial Patterns of an Urban Population of Texas Horned Lizards

Habitat fragmentation has negative consequences on threatened and endangered species by creating isolated populations. The Texas horned lizard (Phrynosoma cornutum) is experiencing population declines and localized extirpations throughout its range and has been classified as a species of greatest conservation need in Oklahoma, USA. Younger age classes have been poorly studied but may be vital to the stability of remaining populations. To address gaps in knowledge concerning subadult (hatchling and juvenile) morphometrics, survivorship, and home range sizes, we studied 2 cohorts of subadults, for 2 years each, covering their hatching and juvenile years (2016–2019). We used a combination of radio-telemetry and novel harmonic radar methodology to study a closed population of Texas horned lizards in 15 ha of native grassland at Tinker Air Force Base, Oklahoma. Population abundance for adults and juveniles was estimated as 56.5 ± 5.5 lizards and density as 7.96 lizards/ha. Our lowest estimates of survival indicated an average survival probability for the hatchling life stage of 0.285 (95% CI = 0.15–0.44), which is lower than for adults on the site. Average home range size increased from hatchling to adult life stages. Our results will have an immediate effect on the planning and assessment of ongoing headstart and management programs for Texas horned lizards. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.     

A place to land: spatiotemporal drivers of stopover habitat use by migrating birds

Migrating birds require en route habitats to rest and refuel. Yet, habitat use has never been integrated with passage to understand the factors that determine where and when birds stopover during spring and autumn migration. Here, we introduce the stopover‐to‐passage ratio (SPR), the percentage of passage migrants that stop in an area, and use 8 years of data from 12 weather surveillance radars to estimate over 50% SPR during spring and autumn through the Gulf of Mexico and Atlantic coasts of the south‐eastern US, the most prominent corridor for North America’s migratory birds. During stopovers, birds concentrated close to the coast during spring and inland in forested landscapes during autumn, suggesting seasonal differences in habitat function and highlighting the vital role of stopover habitats in sustaining migratory communities. Beyond advancing understanding of migration ecology, SPR will facilitate conservation through identification of sites that are disproportionally selected for stopover by migrating birds.     

Une coopération exemplaire entre entomologistes enançais et américains pendant la crise du Phylloxera en France (1868–1895)

Résumé

Ce travail retrace les événements qui ont conduit à une collaboration exemplaire entre entomologistes enançais et américains (principalement le professeur C. V. Riley) pendant la crise du Phylloxera en France, grâce aux nombreuses archives existant de part et d’autre de I’Atlantique. Une des premiéres questions a été de savoir si le Phylloxera était identique dans les deux pays, prouvant ainsi son origine américaine. Une autre question a été de savoir si ce parasite était la cause ou la conséquence de la maladie de la vigne. Cette question, primordiale car lourde de conséquences sur les plans économique et politique, a vu s’afenonter certains entomologistes enançais (le professeur J. E. Planchon et J. Lichtenstein), tenant de I’hypothèse causale, à ?autres (V. A. Signoret) qui soutenaient que le puceron ne s’installait que sur des vignes malades. II s’est établi une collaboration remarquable entre les entomologistes enançais et C. V. Riley, qui a pu apporter des résultats très convaincants à la thèse causale. Enfin son rôle a été déterminant pour conforter la seule solution à long terme défendue par Planchon et Lichtenstein : la greffe de la vigne enançaise sur des vignes américaines résistantes.