Insect Phenology Research Articles

Different emergence phenology of European grapevine moth (Lobesia botrana, Lepidoptera: Tortricidae) on six varieties of grapes

The phenology of insect emergence affects reproductive success and is especially critical in short-lived species. An increasing number of studies have documented the effects of thermal and other climatic variations and of unpredictable habitats on the timing of adult insect emergence within and between populations and years. Numerous interacting factors may affect the phenology of adult emergence. Host-plant quality and availability is a key factor that has been largely neglected in studies of the phenology of phytophagous insects. The purpose of this study was to determine the effect of host plant characteristics on the rate of larval growth and the pattern of emergence in a wild population of Lobesia botrana (European grapevine moth), a significant pest in European vineyards. The phenology of emergence differed significantly among the six tested varieties of grapes. The percentage of bunches harboring pupae was similar among the different grape varieties, and the total number of pupae collected was similar to the number of emerging adults per bunch. Among the six varieties of grapes, 0-25 pupae were produced on each bunch. Each of the grape varieties had a single wave of emergence, in which males emerged before females, but their emergence phenology differed significantly in Chardonnay, Chasselas, and Pinot grapes. Both genders had extended durations of emergence in Merlot grapes. Together, the present results show that the characteristics of the grape host plant affect the emergence phenology of L. botrana.

Diversity of Forensic Rove Beetles (Coleoptera, Staphylinidae) Associated with Decaying Pig Carcass in a Forest Biotope

Most forensic studies are focused on Diptera pattern colonization while neglecting Coleoptera succession. So far, little information is available on the postmortem colonization by beetles and the decomposition process they initiate under temperate biogeoclimatic countries. These beetles have, however, been referred to as being part of the entomofaunal colonization of a dead body. Forensic entomologists need increased databases detailing the distribution, ecology, and phenology of necrophagous insects, including staphylinids (Coleoptera, Staphylinidae). While pig carcasses are commonly used in forensic entomology studies to surrogate human decomposition and to investigate the entomofaunal succession, very few works have been conducted in Europe on large carcasses. Our work reports the monitoring of the presence of adult rove beetles (Coleoptera, Staphylinidae) on decaying pig carcasses in a forest biotope during four seasons (spring, summer, fall, and winter). A total of 23 genera comprising 60 species of rove beetles were collected from pig carcasses.

How accurate are methods for predicting phenology in New Zealand

Thermal accumulation (degree day) methods are routinely used to predict plant and insect phenology Depending on the data available prediction may involve three separate steps with associated errors estimating daily heat units from maximum and minimum temperatures; interpolating daily maxima and minima from monthly averages; and predicting future monthly averages from past climate potentially including climate change This research investigated the potential error in thermal accumulation totals arising from each of these factors at nine New Zealand sites Ten simple heat unit calculations were tested including two littleknown and three new methods Those utilising the true daily mean temperature performed best followed by 4step triangle and sine approximations Interpolating between monthly mean temperature extremes introduced much error into daily estimates and the use of predicted rather than observed monthly normals further increased error Specific recommendations are made for thermal accumulation methods depending on what temperature data are available

Mapping asynchrony between gypsy moth egg-hatch and forest leaf-out: Putting the phenological window hypothesis in a spatial context

Spring phenology in temperate forest ecosystems is responding in diverse ways to global climate change, with unknown consequences for insect disturbances that affect forest productivity. Adaptive forest management that anticipates changes in insect disturbance regimes requires an understanding of the mechanistic links between climate and disturbance behavior. Phenological mismatches between insects and their hosts have the potential to modify patterns of defoliation that are a significant disturbance in temperate forests. Yet the frequency and extent of phenological mismatches have not been quantified over forest landscapes. Forest dwelling, spring-feeding defoliators must synchronize larval emergence annually with leaf-out phenology of host trees. Lack of synchrony can limit population expansion, unless dispersing larvae successfully locate phenologically compatible hosts. We quantified the potential for successful dispersal of an introduced defoliator in a forest landscape by mapping phenological asynchrony from 2000 to 2010. Maps compared MODIS derived leaf-out with gypsy moth egg-hatch from the BioSIM insect phenology model. Mean temporal differences between gypsy moth egg-hatch and leaf-out were sufficient (<−5 or >+10days) to severely limit 1st instar survival in 5 of 11years. Biologically meaningful phenological asynchrony extended over distances of 3.1–4.9km, well beyond typical gypsy moth dispersal thresholds (<1km), meaning that larvae in some parts of the landscape were unable to escape unfavorable phenology by dispersing. Significant spatial heterogeneity in phenological asynchrony clarifies its potential to affect gypsy moth population dynamics and patterns of defoliation disturbance, in contrast with previous field-based research conducted at smaller spatial scales. Our results suggest that delay of leaf-out in this ecosystem due to inadequate winter chilling may disrupt gypsy moth disturbances, as years where host forest phenology is significantly asynchronous over a majority of the landscape become more common. Our modeling approach is relevant and applicable to a wide range of ecological phenomena that require synchrony of phenological interactions across trophic levels. The results inform forest management by illustrating areas in host dominated landscapes that are most susceptible to defoliation in a given year, allowing for improved planning of insect suppression activities.

Identifying environmental drivers of insect phenology across space and time:Culicoidesin Scotland as a case study

Interpreting spatial patterns in the abundance of species over time is a fundamental cornerstone of ecological research. For many species, this type of analysis is hampered by datasets that contain a large proportion of zeros, and data that are overdispersed and spatially autocorrelated. This is particularly true for insects, for which abundance data can fluctuate from zero to many thousands in the space of weeks. Increasingly, an understanding of the ways in which environmental variation drives spatial and temporal patterns in the distribution, abundance and phenology of insects is required for management of pests and vector-borne diseases. In this study, we combine the use of smoothing techniques and generalised linear mixed models to relate environmental drivers to key phenological patterns of two species of biting midges, Culicoides pulicaris and C. impunctatus, of which C. pulicaris has been implicated in transmission of bluetongue in Europe. In so doing, we demonstrate analytical tools for linking the phenology of species with key environmental drivers, despite using a relatively small dataset containing overdispersed and zero-inflated data. We demonstrate the importance of landcover and climatic variables in determining the seasonal abundance of these two vector species, and highlight the need for more empirical data on the effects of temperature and precipitation on the life history traits of palearctic Culicoides spp. in Europe.

A novel trapping system for monitoring insect flight heights

AbstractAn inexpensive, easily constructed, and effective trapping system for capturing flying insects is described. The trapping system is a pole with multiple moveable bowls. The catch is preserved in a killing solution (propylene glycol) between monitoring intervals. Applications for this trapping system include evaluating effects of insect phenology, climate factors, habitat preferences, climatic conditions, and trap colour and interactions of these factors.

Spatial and Temporal Variability of Macroinvertebrates in Spawning and Non-Spawning Habitats during a Salmon Run in Southeast Alaska

Spawning salmon create patches of disturbance through redd digging which can reduce macroinvertebrate abundance and biomass in spawning habitat. We asked whether displaced invertebrates use non-spawning habitats as refugia in streams. Our study explored how the spatial and temporal distribution of macroinvertebrates changed during a pink salmon (Oncorhynchus gorbuscha) spawning run and compared macroinvertebrates in spawning (riffle) and non-spawning (refugia) habitats in an Alaskan stream. Potential refugia included: pools, stream margins and the hyporheic zone, and we also sampled invertebrate drift. We predicted that macroinvertebrates would decline in riffles and increase in drift and refugia habitats during salmon spawning. We observed a reduction in the density, biomass and taxonomic richness of macroinvertebrates in riffles during spawning. There was no change in pool and margin invertebrate communities, except insect biomass declined in pools during the spawning period. Macroinvertebrate density was greater in the hyporheic zone and macroinvertebrate density and richness increased in the drift during spawning. We observed significant invertebrate declines within spawning habitat; however in non-spawning habitat, there were less pronounced changes in invertebrate density and richness. The results observed may be due to spawning-related disturbances, insect phenology, or other variables. We propose that certain in-stream habitats could be important for the persistence of macroinvertebrates during salmon spawning in a Southeast Alaskan stream.

Diversity, Phenology, and Natural History of Insects and other Arthropods in The Far Side ® by Gary Larson

Diversity, Phenology, and Natural History of Insects and other Arthropods in The Far Side ® by Gary Larson

Genetically Engineered Bt Corn and Range Expansion of the Western Bean Cutworm (Lepidoptera: Noctuidae) in the United States: A Response to Greenpeace Germany

The western bean cutworm, Striacosta albicosta (Smith), is a pest of corn and dry beans in North America. Before the late 1990s, economic infestations of the insect were restricted mostly to the western Great Plains and Idaho. During 1999–2009, it greatly expanded its range and moved across the central and eastern regions of the Corn Belt, eventually reaching northeastern Atlantic coast states. Greenpeace Germany issued a 2010 report claiming that the dramatic range expansion of the western bean cutworm was due entirely to “pest replacement” that resulted from the adoption of genetically engineered Bt corn, which suppressed one pest species and allowed another species—the western bean cutworm, in this case—to take its place. We maintain that the scientific literature does not provide empirical field-collected data to support the Greenpeace Germany claim that Bt corn is the sole factor that influenced the range expansion of the western bean cutworm. We propose broader ecological and agronomic factors to explain why the western bean cutworm has recently expanded its geographic range to include all of the major corn-growing areas in the central and eastern United States. These additional factors may include insect biology, insect and corn phenology synchrony, reduced insecticide use, conservation tillage, soil type, glyphosate-resistant crops, insect genetics, insect pathogens, preexisting insect population densities, and climate change.

Disentangling the paradox of insect phenology: are temporal trends reflecting the response to warming?

The strength and direction of phenological responses to changes in climate have been shown to vary significantly both among species and among populations of a species, with the overall patterns not fully resolved. Here, we studied the temporal and spatial variability associated with the response of several insect species to recent global warming. We use hierarchical models within a model comparison framework to analyze phenological data gathered over 40 years by the Japan Meteorological Agency on the emergence dates of 14 insect species at sites across Japan. Contrary to what has been predicted with global warming, temporal trends of annual emergence showed a later emergence day for some species and sites over time, even though temperatures are warming. However, when emergence data were analyzed as a function of temperature and precipitation, the overall response pointed out an earlier emergence day with warmer conditions. The apparent contradiction between the response to temperature and trends over time indicates that other factors, such as declining populations, may be affecting the date phenological events are being recorded. Overall, the responses by insects were weaker than those found for plants in previous work over the same time period in these ecosystems, suggesting the potential for ecological mismatches with deleterious effects for both suites of species. And although temperature may be the major driver of species phenology, we should be cautious when analyzing phenological datasets as many other factors may also be contributing to the variability in phenology.

An examination of synchrony between insect emergence and flowering in Rocky Mountain meadows

One possible effect of climate change is the generation of a mismatch in the seasonal timing of interacting organisms, owing to species-specific shifts in phenology. Despite concerns that plants and pollinators might be at risk of such decoupling, there have been few attempts to test this hypothesis using detailed phenological data on insect emergence and flowering at the same localities. In particular, there are few data sets on pollinator flight seasons that are independent of flowering phenology, because pollinators are typically collected at flowers. To address this problem, we established standardized nesting habitat (trap nests) for solitary bees and wasps at sites along an elevational gradient in the Rocky Mountains, and monitored emergence during three growing seasons. We also recorded air temperatures and flowering phenology at each site. Using a reciprocal transplant experiment with nesting bees, we confirmed that local environmental conditions are the primary determinants of emergence phenology. We were then able to develop phenology models to describe timing of pollinator emergence or flowering, across all sites and years, as a function of accumulated degree-days. Although phenology of both plants and insects is well described by thermal models, the best models for insects suggest generally higher threshold temperatures for development or diapause termination than those required for plants. In addition, degree-day requirements for most species, both plants and insects, were lower in locations with longer winters, indicating either a chilling or vernalization requirement that is more completely fulfilled at colder sites, or a critical photoperiod before which degree-day accumulation does not contribute to development. Overall, these results suggest that phenology of plants and trap-nesting bees and wasps is regulated in similar ways by temperature, but that plants are more likely than insects to advance phenology in response to springtime warming. We discuss the implications of these results for plants and pollinators, and suggest that phenological decoupling alone is unlikely to threaten population persistence for most species in our study area.

Carrion beetles visiting pig carcasses during early spring in urban, forest and agricultural biotopes of Western Europe.

Carrion beetles are important in terrestrial ecosystems, consuming dead mammals and promoting the recycling of organic matter into ecosystems. Most forensic studies are focused on succession of Diptera while neglecting Coleoptera. So far, little information is available on carrion beetles postmortem colonization and decomposition process in temperate biogeoclimatic countries. These beetles are however part of the entomofaunal colonization of a dead body. Forensic entomologists need databases concerning the distribution, ecology and phenology of necrophagous insects, including silphids. Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate entomofaunal succession. However, few studies have been conducted in Europe on large carcasses. The work reported here monitored the presence of the carrion beetles (Coleoptera: Silphidae) on decaying pig carcasses in three selected biotopes (forest, crop field, urban site) at the beginning of spring. Seven species of Silphidae were recorded: Nicrophorus humator (Gleditsch), Nicrophorus vespillo (L.), Nicrophorus vespilloides (Herbst), Necrodes littoralis L., Oiceoptoma thoracica L., Thanatophilus sinuatus (Fabricius), Thanatophilus rugosus (L.). All of these species were caught in the forest biotope, and all but O. thoracica were caught in the agricultural biotope. No silphids were caught in the urban site.

Diapause induction and termination in a commonly univoltine leaf beetle (Phratora vulgatissima)

Abstract The leaf beetle Phratora vulgatissima (Linnaeus 1758) is commonly univoltine in south-central Sweden but may sometimes initiate a partial second generation. The current study was set out to investigate under what abiotic conditions the beetles initiate a second generation. Using climate chamber experiments, the beetles were shown to have a facultative reproductive diapause induced by declining day-length. The critical day-length (CDL) for diapause induction was estimated to be 18 h and 10 min. In the field, first-generation beetles developing to adulthood before August in 2009 became reproductively active and produced a second generation, but most individuals emerged later and were in reproductive diapause. P. vulgatissima overwinter as adults and diapause was shown to be maintained until mid-winter in 2008/2009. The cumulative temperature requirement for oviposition after diapause termination was estimated to be 222 day-degrees with a 5.5°C temperature threshold. Three different day-degree models that were developed to predict the phenology of female oviposition in the spring were validated by comparing model results with field data on the timing of oviposition in previous years. The study suggests that P. vulgatissima may initiate a second generation in Sweden if development of the first generation is completed before August. Warmer spring and summer temperatures due to ongoing climate change may cause advanced insect phenology and faster completion of insect life-cycles at northern latitudes, which will affect the proportion of insects that initiate a second generation.

Predicting insect phenology across space and time

Many species appear to be undergoing shifts in phenology, arising from climate change. To predict the direction and magnitude of future changes requires an understanding of how phenology depends on climatic variation. Species show large-scale spatial variation in phenology (affected by differentiation among populations) as well as variation in phenology from year-to-year at the same site (affected predominantly by local plasticity). Teasing apart spatial and temporal variation in phenology should allow improved predictions of phenology under climate change. This study is the first to quantify large-scale spatial and temporal variation in the entire emergence pattern of species, and to test the relationships found by predicting future data. We use data from up to 33 years of permanent transect records of butterflies in the United Kingdom to fit and test models for 15 butterfly species. We use generalized additive models to model spatial and temporal variation in the distribution of adult butterflies over the season, allowing us to capture changes in the timing of emergence peaks, relative sizes of peaks and/or number of peaks in a single analysis. We develop these models using data for 1973–2000, and then use them to predict phenologies from 2001 to 2006. For six of our study species, a model with only spatial variation in phenology is the best predictor of the future, implying that these species have limited plasticity. For the remaining nine species, the best predictions come from a model with both spatial and temporal variation in phenology; for four of these, growing degree-days have similar effects over space and time, implying high levels of plasticity. The results show that statistical phenology models can be used to predict phenology shifts in a second time period, suggesting that it should be feasible to project phenologies under climate change scenarios, at least over modest time scales.

Phenology of aquatic insects in a protected wetland (Natura 2000 network) in northwestern Spain

espanolEl objetivo principal de este estudio fue aportar nuevos datos al conocimiento sobre los ciclos de vida de varias especies de insectos acuaticos en un humedal protegido, las de (Galicia, NO Espana), incluido en la Red Natura 2000. Se muestrearon tres lagunas y cuatro arroyos mensualmente durante un ano (2004-2005) mediante un metodo semicuanti­tativo. Se midieron las larvas y ninfas de trece especies, y se analizaron sus ciclos de vida. Todas las especies presentaron ciclos univoltinos o semivoltinos. Tambien se examino la posible correlacion entre la longitud de las larvas y ninfas, y la temperatura del agua. Se encontro una correlacion significativa para dos especies, el coleoptero acuatico Noterus laevis, y la libelula (Boyeria irene). Es importante destacar la presencia de una especie incluida en la Directiva Habitats, el caballito del diablo (Coenagrion mercuriale). EnglishThe aim of this study was to gather new data about the life cycle phenologies of several species of aquatic insects in the Gandaras de Budino (Galicia, NW Spain) protected wetland, included in the Natura 2000 network. During an annual cycle (2004-2005), three shallow lakes and four streams were sampled monthly using a semi-quantitative sampling method. The body lengths of the larvae and nymphs of thirteen species were measured, and their life cycles were analysed. All species had univoltine or semivoltine cycles. Additionally, a possible correlation between larval and nymphal lengths and water temper­ature was examined. We found a significant correlation for two species: the water beetle (Note rus laevis) and the dragonfly (Boyeria Irene). It is important to highlight the presence in the studied area of a species included in the Habitats Directive: the damselfly (Coenagrion mercuriale).

Similar breakdown rates and benthic macroinvertebrate assemblages on native and Eucalyptus globulus leaf litter in Californian streams

Summary1. Eucalyptus globulus, a tree species planted worldwide in many riparian zones, has been reported to affect benthic macroinvertebrates negatively. Although there is no consensus about the effects of Eucalyptus on aquatic macrobenthos, its removal is sometimes proposed as a means of ecological restoration.2. We combined the sampling of macroinvertebrates with measurement of the colonisation of leaf packs in mesh bags, to examine the effects of riparian Eucalyptus and its litter on benthic macroinvertebrates in three small streams in California, U.S.A. Each stream included one reach bordered by Eucalyptus (E‐site) and a second bordered by native vegetation (N‐site).3. The macrobenthos was sampled and two sets of litter bags were deployed at each site: one set with Eucalyptus litter (Euc‐bags) and one with mixed native tree litter (Nat‐bags) containing Quercus, Umbellularia, Acer and Alnus. Bags were exposed for 28, 56 and 90 days and this experiment was repeated in the autumn, winter and spring to account for effects of changing stream flow and insect phenology.4. Litter input (average dry mass: 950 g m−2 year−1 in E‐sites versus 669 g m−2 year−1 in N‐sites) was similar, although in‐stream litter composition differed between E‐ and N‐sites. Litter broke down at similar rates in Euc‐bags and Nat‐bags (0.0193 day−1 versus 0.0134 day−1), perhaps reflecting the refractory nature of some of the leaves of the native trees (Quercus agrifolia).5. Summary metrics for macroinvertebrates (taxon richness, Shannon diversity, pollution tolerance index) did not differ significantly between the E and N sites, or between Euc‐bags and Nat‐bags. No effect of exposure time or site was detected by ordination of the taxa sampled. However, distinct seasonal ordination clusters were observed in winter, spring and autumn, and one of the three streams formed a separate cluster.6. The presence of Eucalyptus was less important in explaining the taxonomic composition of the macrobenthos than either ‘season’ or ‘stream’. Similarly, these same two factors (but not litter species) also helped explain the variation in leaf breakdown. We conclude that patches of riparian Eucalyptus and its litter have little effect on stream macrobenthos in this region.

Spawning salmon and the phenology of emergence in stream insects

Phenological dynamics are controlled by environmental factors, disturbance regimes and species interactions that alter growth or mortality risk. Ecosystem engineers can be a key source of disturbance, yet their effects on the phenologies of co-occurring organisms are virtually unexplored. We investigated how the abundance of a dominant ecosystem engineer, spawning sockeye salmon (Oncorhynchus nerka), alters the emergence phenology of stream insects. In streams with high densities of salmon, peak insect emergence occurred in early July, immediately prior to salmon spawning. By contrast, peak insect emergence in streams with low densities of salmon was weeks later and more protracted. The emergence of specific taxa was also significantly related to salmon density. A common rearing experiment revealed that differences in emergence timing are maintained in the absence of spawning salmon. We hypothesize that these patterns are probably driven by predictable and severe disturbance from nest-digging salmon driving local adaptation and being a trait filter of insect emergence. Thus, salmon regulate the timing and duration of aquatic insect emergence, a cross-ecosystem flux from streams to riparian systems.

Modeling the Effects of Developmental Variation on Insect Phenology

Phenology, the timing of developmental events such as oviposition or pupation, is highly dependent on temperature; since insects are ectotherms, the time it takes them to complete a life stage (development time) depends on the temperatures they experience. This dependence varies within and between populations due to variation among individuals that is fixed within a life stage (giving rise to what we call persistent variation) and variation from random effects within a life stage (giving rise to what we call random variation). It is important to understand how both types of variation affect phenology if we are to predict the effects of climate change on insect populations.We present three nested phenology models incorporating increasing levels of variation. First, we derive an advection equation to describe the temperature-dependent development of a population with no variation in development time. This model is extended to incorporate persistent variation by introducing a developmental phenotype that varies within a population, yielding a phenotype-dependent advection equation. This is further extended by including a diffusion term describing random variation in a phenotype-dependent Fokker-Planck development equation. These models are also novel because they are formulated in terms of development time rather than developmental rate; development time can be measured directly in the laboratory, whereas developmental rate is calculated by transforming laboratory data. We fit the phenology models to development time data for mountain pine beetles (MPB) (Dendroctonus ponderosae Hopkins [Coleoptera: Scolytidae]) held at constant temperatures in laboratory experiments. The nested models are parameterized using a maximum likelihood approach. The results of the parameterization show that the phenotype-dependent advection model provides the best fit to laboratory data, suggesting that MPB phenology may be adequately described in terms of persistent variation alone. MPB phenology is simulated using phloem temperatures and attack time distributions measured in central Idaho. The resulting emergence time distributions compare favorably to field observations.

Context-dependent Changes in the Weighting of Environmental Cues That Initiate Breeding in a Temperate Passerine, the Corsican Blue Tit (Cyanistes caeruleus)

ABSTRACT. Birds use local environmental cues to fine-tune the timing of egg laying such that the nestling period normally coincides with the local peak in food availability. Ambient temperature, vegetation phenology, and insect phenology are often considered the most likely cues, but no previous studies have explicitly compared and partitioned their relative effects. We used confirmatory path analyses and a long-term study of Blue Tits (Cyanistes caeruleus) to identify and measure the relative weighting of the causal paths that link laying date to spring phenology and temperature in deciduous and evergreen oak forests on Corsica. Path analysis showed that the effects of temperature and vegetation phenology vary between forest types and season. In deciduous oak forest, where females lay eggs early in spring, phenology of vegetation or insects sets the laying date. In evergreen oak forest, where breeding occurs later in the season, females shift from a predominantly phenology-based cue system to a predomina...

P39 Internet use in older and younger breast cancer patients in a district general hospital

Insect phenologies are changing in response to climate warming. Shifts toward earlier seasonal activity are widespread; however, responses of insect phenology to warming are often more complex. Many species have prolonged their activity periods; others have shown delays. Furthermore, because of interspecific differences in temperature sensitivity, warming can increase or decrease synchronization between insects and their food plants and natural enemies. Here, I review recent findings in three areas — shifts in phenology, changes in voltinism, and altered species interactions — and highlight counterintuitive responses to warming caused by the particularities of insect life cycles. Throughout, I emphasize how an appreciation of the evolutionary processes shaping insect life histories is necessary to forecast changes in insect phenology and their demographic consequences.