Search

Range expansions-whether permanent or transient-strongly influence the distribution of genetic variation in space. Monarch butterflies are best known for long-distance seasonal migration within North America but are also established as nonmigratory populations around the world, including on Pacific Islands. Previous research has highlighted stepwise expansion across the Pacific, though questions remain about expansion timing and the population genetic consequences of migration loss. Here, we present reduced-representation sequencing data for 275 monarchs from North America (n = 85), 12 Pacific Islands (n = 136) and three locations in Australia (n = 54), with the goal of understanding (i) how the monarch's Pacific expansion has shaped patterns of population genetic variation and (ii) how loss of migration has influenced spatial patterns of differentiation. We find support for previously described stepwise dispersal across the Pacific and document an additional expansion from Hawaii into the Mariana Islands. Nonmigratory monarchs within the Mariana Islands show strong patterns of differentiation, despite their proximity; by contrast, migratory North American samples form a single genetically panmictic population across the continent. Estimates of Pacific establishment timing are highly uncertain (~100-1,000,000 years ago) but overlap with historical records that indicate a recent expansion. Our data support (i) a recent expansion across the Pacific whose timing overlaps with available historical records of establishment and (ii) a strong role for seasonal migration in determining patterns of spatial genetic variation. Our results are noteworthy because they demonstrate how the evolution of partial migration can drive population differentiation over contemporary timescales.

The Bag‐shelter moth, Ochrogaster lunifer (Lepidoptera: Notodontidae), is an Australian endemic species of Thaumetopoeinae with a univoltine life cycle and gregarious, herbivorous larvae. It is variable throughout its range across the continent, most noticeably by the species of host tree used and nest‐building behaviour. It has long been considered a species complex by some taxonomists, and the lack of gene flow between populations of ground‐nesters and above‐ground nesters at the same sites provides strong evidence for at least two species. We tested the specificity of host use and nesting behaviour of ground‐nesting and trunk‐nesting forms of O. lunifer by transplanting field‐collected egg masses to the other form's host, either in their natural position or in the position used by the other form. At the study site, ground‐nesting and trunk‐nesting (tree‐hugger) O. lunifer coexist. Ground‐nesting larvae are found on Acacia spp., and egg masses are laid at the base of host tree trunks where nests develop whereas tree‐hugger larvae are found on Blakella tessellaris, egg masses are laid in the outer canopy, and nests develop on the trunk or large branches. Of the 47 egg masses of O. lunifer transplanted to the unnatural host, only one cohort of tree‐hugger larvae developed through to adult moths. Placing an egg mass in its unnatural position on its natural host did not prevent the larvae from developing and successfully establishing nests for either nesting‐form, although all the ground‐nesters moved position (from the canopy to the ground) and the tree‐huggers mostly did not (from the ground to the canopy). Only the tree‐hugger form of O. lunifer developed a viable nest on the unnatural host species, established a nest at the unnatural oviposition site, and shared that nest with larvae of the other nesting‐form, suggesting tree‐hugger larvae are somewhat plastic in their behaviour and ecology. Our findings add to previous studies indicating that Acacia is likely the ancestral host of O. lunifer though large areas of its range remain unstudied. [ABSTRACT FROM AUTHOR]

Monarch butterflies are best known from their migratory North American range, although many resident, year-round breeding populations are established throughout the world. Here, we evaluate two non-exclusive hypotheses for the loss of migration in resident monarch populations: (1) absence of cues that trigger migration; and (2) loss of sensory, neural or physiological systems required for migration. To evaluate the first hypothesis, we exposed resident monarchs from Queensland, Australia to decreasing larval photoperiod and observed reproductive development in resulting females to assess their propensity to show reduced reproductive development, a precursor for long-distance migration. To address the second hypothesis, we measured antennal circadian clock gene expression, a crucial element of the monarch's ability to orientate directionally, in a resident and a migratory population. We found that Australian resident monarchs show reduced reproductive development in response to decreasing photoperiod, consistent with the 'loss of cues' hypothesis. We found no differences in antennal clock gene expression between migratory and resident populations, inconsistent with the 'loss of mechanism' hypothesis. Together, these data indicate that even after hundreds of generations of non-migration, monarchs retain two crucial elements of their migratory repertoire: developmental plasticity associated with decreasing photoperiod and antennal circadian rhythms necessary for directional orientation.

Understanding how landscape composition and configuration drive the dynamics of pests and their various natural enemies is crucial to enhance biological control services (biocontrol). Geographic variability in landscape effects prompts questions about whether this is due to genuine differences or methodological differences among studies, given that most studies are conducted in a single region. This study investigated how the ecological function of parasitoids and predators responds to landscape traits in three regions encompassing an agriculture intensification gradient. The effects of landscape structure and configuration differed among regions and natural enemies. Non-crop habitats increased the abundance of parasitoids only in two less intensified regions presumably due to insufficient amount of non-crop habitats in the intensified region (typically < 10%). Nevertheless, their biological control efficiency (BCE) was consistently increased by non-crop habitats across regions. Higher maize proportion increased predator abundance and their BCE in the two nonmountainous regions. The value of maize as a source habitat for predators may have been limited in the mountainous region due to the lower aphid abundances there. Edge density positively affected abundances of predators and parasitoids, but only positively increased the BCE of all natural enemies combined. Inconsistent regional responses to the same landscape variables suggest that a uniform integrated pest management strategy for alfalfa is impractical. However, increasing edge density should be a useful first step for supporting diverse natural enemy communities and their biocontrol potential. [ABSTRACT FROM AUTHOR]

The invasive apple wood borer Agrilus mali Matsumura (Coleoptera: Buprestidae) threatens the viability of wild apple forests in Xinjiang, China, imperiling the preservation of apple germplasm resources in Central Eurasia. Pruning infested branches can reduce the likelihood of outbreaks of various pests and associated damage, but its efficacy and feasibility for managing A. mali has not been well-studied. Therefore, we examined the efficacy of pruning at three different times of the year in commercial orchards in 2018 and 2019. We evaluated the efficacy of pruning for longer-term sustainable management of A. mali in wild apple forests over a five-year period from 2016–2019. Autumn pruning resulted in mortality of all immature A. mali in pruned branches, increased flowering in individual trees, and a significant reduction in both pest density and tree damage on the landscape. Simulation modeling showed that a single well-timed pruning treatment could maintain low pest density for at least 6–10 years. Recurring pruning schedules may be an effective long-term management tool, suppressing A. mali populations in wild apple forests and facilitating ecosystem recovery. This practical tactic could prove instrumental in managing A. mali and sustaining ecosystem health, particularly in the face of future invasions in wild apple forests in central Eurasia. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Lepidoptera: Gelechiidae) originates from the South American tropics but has become a major invasive pest of tomato and other Solanaceae crops worldwide. Agricultural protected facilities (APFs) such as greenhouses and plastic tunnels may provide thermal conditions that allow the survival of T. absoluta in temperate zones with cold winters. In this study, a CLIMEX model was used to investigate the dual effects of increasing use of APFs and climate warming on the potential distribution and seasonal dynamics of T. absoluta in China. Our model showed that the northern boundary for year-round population persistence in China, ignoring APFs, was approximately 30°N, covering about 21% of China's area suitable under current climate. The modelled suitable area increased to 31% and northern boundary for year-round population persistence shifted to 40°N in 2080 under global warming. When APF refuges are included, the potential suitable area was 78% under the current climate and 79% under global warming. This suggests that, in the future, the increasing use of APFs will increase the areas at risk of T. absoluta invasion significantly more than global warming because APFs effectively protect T. absoluta from harsh northern winters. In addition, vegetable production in surrounding open fields will be at risk of invasion during milder seasons when APFs are opened and T. absoluta can disperse. Therefore, the micro-climate of APFs should be considered as part of the invasion process, and Integrated Pest Management should be simultaneously implemented inside and outside APFs for the rational management T. absoluta. [ABSTRACT FROM AUTHOR]

Lepidoptera can cause several health issues in humans and domestic animals due to their setae, which are defensive adaptations that protect them from predators. The diversity of venomous Lepidoptera has been explored in several reviews starting from the first comprehensive attempt in 1984 by Kawamoto and Kumada (KK) who compiled a list of 228 species based on previous reviews; however, KK did not cite the original publications for listed species. In this review we validated and updated the KK table. The updated list of venomous Lepidoptera includes 5 superfamilies, 14 families, 208 genera, and 576 species, representing a two-fold increase for genera and 2.9-fold for species with respect to KK. The total number of species in the genera including at least one venomous species, which we argue is likely closer to the true number of venomous species, is 7 times higher (3,620). GBIF (Global Biodiversity Information Facility) occurrences for venomous species are 1-4 orders of magnitude higher than those of confamilial non-venomous species. The presence of venomous structures is independent of the relatedness of the clades or geographic region; venom is produced by many species of Zygaenoidea, Lasiocampoidea and Bombycoidea but only by some specialized groups in Papilionoidea and Noctuoidea. There are likely to be multiple evolutionary origins of venom within Lepidoptera, but the exact number is difficult to estimate. The knowledge gap between medical and natural history fields needs to be addressed with novel approaches to study ecology and toxicology. This review offers health practitioners a tool to better understand the origin of the reactions observed and to improve the identification of the causal agents. [ABSTRACT FROM AUTHOR]

Evolutionary principles are now routinely incorporated into medicine and agriculture. Examples include the design of treatments that slow the evolution of resistance by weeds, pests, and pathogens, and the design of breeding programs that maximize crop yield or quality. Evolutionary principles are also increasingly incorporated into conservation biology, natural resource management, and environmental science. Examples include the protection of small and isolated populations from inbreeding depression, the identification of key traits involved in adaptation to climate change, the design of harvesting regimes that minimize unwanted life-history evolution, and the setting of conservation priorities based on populations, species, or communities that harbor the greatest evolutionary diversity and potential. The adoption of evolutionary principles has proceeded somewhat independently in these different fields, even though the underlying fundamental concepts are the same. We explore these fundamental concepts under four main themes: variation, selection, connectivity, and eco-evolutionary dynamics. Within each theme, we present several key evolutionary principles and illustrate their use in addressing applied problems. We hope that the resulting primer of evolutionary concepts and their practical utility helps to advance a unified multidisciplinary field of applied evolutionary biology.