Urbanization extends flight phenology and leads to local adaptation of seasonal plasticity in Lepidoptera

Urbanization is gaining force globally, which challenges biodiversity, and it has recently also emerged as an agent of evolutionary change. Seasonal phenology and life cycle regulation are essential processes that urbanization is likely to alter through both the urban heat island effect (UHI) and artificial light at night (ALAN). However, how UHI and ALAN affect the evolution of seasonal adaptations has received little attention. Here, we test for the urban evolution of seasonal life-history plasticity, specifically changes in the photoperiodic induction of diapause in two lepidopterans, Pieris napi (Pieridae) and Chiasmia clathrata (Geometridae). We used long-term data from standardized monitoring and citizen science observation schemes to compare yearly phenological flight curves in six cities in Finland and Sweden to those of adjacent rural populations. This analysis showed for both species that flight seasons are longer and end later in most cities, suggesting a difference in the timing of diapause induction. Then, we used common garden experiments to test whether the evolution of the photoperiodic reaction norm for diapause could explain these phenological changes for a subset of these cities. These experiments demonstrated a genetic shift for both species in urban areas toward a lower daylength threshold for direct development, consistent with predictions based on the UHI but not ALAN. The correspondence of this genetic change to the results of our larger-scale observational analysis of in situ flight phenology indicates that it may be widespread. These findings suggest that seasonal life cycle regulation evolves in urban ectotherms and may contribute to ecoevolutionary dynamics in cities.

Red-headed ash borer Neoclytus acuminatus acuminatus (Fabricius) (Coleoptera: Cerambycidae): the global distribution, current spreading and the seasonal activity depending on its different habitats

Holarctic expansion of Neoclytus acumiantus acuminatus due to its polyphagous character has been a major concern for plant health, which raises several questions about its spreading directions. I have examined all bibliographical references, phytosanitary reports and authentic photographs from the online sources in the quest of the determination of the worldwide distribution and flight phenology of N. a. acuminatus. The expansion, including the western Palearctic regions as well as several Neotropical habitats, is proven and has become more intense in the last decades. It can be found mostly on the Holarctic region including 21 countries, which is supported by 51 publications. Its spreading mostly northward and eastward in the Palearctic is continuous due to anthropogenic effects, climate change as well as movement of infested materials. Flight phenology and population densities as a function of habitats were mapped. The detection in novel habitats of this pest due to imported wood materials and products is envisaged in the foreseeable future. The primary criterion for controlling the species adapted to the commercial trade and climatic change would be the elaboration of a monitoring system in affected and exposed areas.

Combining range and phenology shifts offers a winning strategy for boreal Lepidoptera

Species can adapt to climate change by adjusting in situ or by dispersing to new areas, and these strategies may complement or enhance each other. Here, we investigate temporal shifts in phenology and spatial shifts in northern range boundaries for 289 Lepidoptera species by using long-term data sampled over two decades. While 40% of the species neither advanced phenology nor moved northward, nearly half (47%) -used one of the two strategies. The strongest positive population trends was observed for the minority of species (13%) that both advanced flight phenology and shifted their northern range boundaries northward. We show that, for Boreal Lepidoptera, a combination of phenology and range shifts is the most viable strategy under a changing climate. Effectively, this may divide species into winners and losers based on their propensity to capitalize on this combination, with potentially large consequences on future community composition.

Identification of a Male-Produced Volatile Pheromone for Phymatodes dimidiatus (Coleoptera: Cerambycidae) and Seasonal Flight Phenology of Four Phymatodes Species Endemic to the North American Intermountain West

Research over the last 15 yr has shown widespread pheromone parsimony within the coleopteran family Cerambycidae, with a number of highly conserved pheromone motifs, often shared within and across subfamilies, tribes, and genera. Our goals were to increase our understanding of the evolution of volatile pheromones within the Cerambycidae, their role in reproductive isolation and to identify pheromones for use in the development of lures for monitoring cerambycids. Over 3 yr, we tested 12 compounds known to be cerambycid pheromones as possible attractants at sites across Idaho. This study focused on species within the cerambycine genus Phymatodes (Tribe: Callidiini). We also collected and analyzed headspace volatiles of captured Phymatodes dimidiatus (Kirby). Our results demonstrate that (R)-2-methylbutan-1-ol is a male-produced volatile pheromone for P. dimidiatus. These results are consistent with prior research suggesting that (R)-2-methylbutan-1-ol and (R)-3-hydroxyhexan-2-one, individually or in a blend of both compounds, commonly serve as pheromones for Phymatodes spp. We captured Phymatodes starting in mid-May, continuing through mid-August. Our data indicate that flight periods of Phymatodes spp. in Idaho overlap. These species may be utilizing various mechanisms to ensure reproductive isolation, such as the production of different volatile pheromones, minor components, and/or proportions of components, utilizing different host species and/or host volatiles, differing daily activity periods, and/or occupying different heights in the tree canopy. Our results contribute to the basic understanding of the chemical and behavioral ecology of the Cerambycidae and can be applied to the development of pheromone lures for monitoring of economically important or endangered species.

Effects of Site Thermal Variation and Physiography on Flight Synchrony and Phenology of the North American Spruce Beetle (Coleoptera: Curculionidae, Scolytinae) and Associated Species in Colorado

Spruce beetle, Dendroctonus rufipennis Kirby, is associated with forest mortality in Colorado and across western North America, yet it is not well understood how thermal variability affects basic population processes such as flight phenology. However, phenology–temperature relationships are important for understanding patterns of ecosystem disturbance, especially under projected climate warming. Here, we use a multiyear trapping study to test the hypothesis that spruce beetle flight synchrony, timing, and fitness traits (body size) are affected by variation in regional temperature and physiography. Large quantities of co-colonizing scolytines (Polygraphus convexifrons) (Coleoptera: Curculionidae, Scolytinae) and predatory beetles (Thanasimus undulatus) (Coleoptera: Cleridae) that may affect D. rufipennis populations also responded to spruce beetle synthetic pheromone lures. Relationships between flight patterns and environmental conditions were also analyzed for these species. The winter of 2018 was warmer and drier than winter 2017 and was associated with earlier flight for both scolytine species across most sites. The most important environmental factor driving D. rufipennis flight phenology was accumulated growing degree-days, with delayed flight cessation under warmer conditions and larger beetles following a warm winter. Flight was consistently more synchronous under colder growing season conditions for all species, but synchrony was not associated with winter temperatures. Warmer-than-average years promoted earlier flight of D. rufipennis and associated species, and less synchronous, prolonged flight across the region. Consequently, climate warming may be associated with earlier and potentially extended biotic pressure for spruce trees in the Rocky Mountain region, and flight phenology of multiple scolytines is plastic in response to thermal conditions.

Flight phenology and trap selection for monitoring potential viral vector Aphididae and Aleyrodidae (Hemiptera) in strawberry (Rosaceae) fields of Québec, Canada

Strawberry decline disease, predominantly viral in origin, was a serious threat to the strawberry (Fragaria x ananassaDuchesne ex Rozier; Rosaceae) fields of Québec, Canada, between 2012 and 2014. Our aim was to monitor the abundance and activity of the main insect vectors: the strawberry aphid,Chaetosiphon fragaefolii(Cockerell) (Hemiptera: Aphididae) and the greenhouse whitefly,Trialeurodes vaporariorumWestwood (Hemiptera: Aleyrodidae). First, we compared the effectiveness of two trapping techniques, the yellow sticky trap and the yellow pan trap. Results showed that the sticky traps are more effective in capturing alates in flight. Second, we determined the peak flight period for each of the two vectors in several locations within the province of Québec. Results suggest that the peak abundance of wingedC. fragaefoliiis during the first two weeks of August, while the peak abundance ofT. vaporariorumis in the last two weeks of September. Overall trap captures also found 53 different species of winged aphids, and we documented a new distribution record on commercial strawberry fields in Québec,Aleyrodes spiraeoides(Quaintance) (Hemiptera: Aleyrodidae). Species composition and significant information of flight periods will be useful for the management of virus-transmitting insects associated with strawberry decline disease in Québec.

FLIGHT PHENOLOGY OF VESPID WASPS (HYMENOPTERA, VESPIDAE) IN NORTHERN MONGOLIA

Flight phenology of forty-one vespid species were determined in northern Mongolia, using published data and our own samples. The studied species were divided into four phenological groups (summer species, late-summer species, summer-early autumn species and multi-seasonal species) depending on overlapping periods of the flight. Generally, flight phenology of vespid wasps in northern Mongolia is characterized as short lasting (50-150 days) between early May and late September, and mainly related with local environmental conditions and biology of particular species. Probability of occurrence of each species in particular time of the year was high (r-value ~1). The time of the year coincided for all studied species in a same period of time: from end of June to early August. Running title: Vespidae in northern Mongolia.