Evaluating the invasion risk of longhorn crazy ants (Paratrechina longicornis) in South Korea using spatial distribution model

The longhorn crazy ant (Paratrechina longicornis) is a globally distributed ant species with a high invasion risk, suggesting the need to use species distribution modeling to evaluate its potential distribution. Therefore, this study aimed to predict the potential distribution of longhorn crazy ants in response to climate change by using CLIMEX and Maxent and identifying the climatic factors that influence their habitat. Then, the model outcomes were used to construct an ensemble map to evaluate invasion risk in South Korea. The results indicated that temperature-related variables mainly affect the distribution of the longhorn crazy ant, and the two models showed consensus regions in South America, Africa, Australia, and Southeast Asia. Due to climate change, it was expected that the northern limit would somewhat rise. In South Korea, high-risk areas were predicted to be located along the coasts, but they would expand as a consequence of climate change. Since the invasion of longhorn crazy ants has occurred via commercial trades, a relatively high risk in coastal areas demands a high level of attention. We expect that this study will provide initial insight into selecting areas for longhorn crazy ant quarantine with ensemble species distribution modeling.     

Changes in the distribution of South Korean forest vegetation simulated using thermal gradient indices

To predict changes in South Korean vegetation distribution, the Warmth Index (WI) and the Minimum Temperature of the Coldest Month Index (MTCI) were used. Historical climate data of the past 30 years, from 1971 to 2000, was obtained from the Korea Meteorological Administration. The Fifth-Generation National Center for Atmospheric Research (NCAR) /Penn State Mesoscale Model (MM5) was used as a source for future climatic data under the A1B scenario from the Special Report on Emission Scenario (SRES) of the Intergovernmental Panel on Climate Change (IPCC). To simulate future vegetation distribution due to climate change, the optimal habitat ranges of Korean tree species were delimited by the thermal gradient indices, such as WI and MTCI. To categorize the Thermal Analogy Groups (TAGs) for the tree species, the WI and MTCI were orthogonally plotted on a two-dimensional grid map. The TAGs were then designated by the analogue composition of tree species belonging to the optimal WI and MTCI ranges. As a result of the clustering process, 22 TAGs were generated to explain the forest vegetation distribution in Korea. The primary change in distribution for these TAGs will likely be in the shrinkage of areas for the TAGs related to Pinus densiflora and P. koraiensis, and in the expansion of the other TAG areas, mainly occupied by evergreen broad-leaved trees, such as Camellia japonica, Cyclobalanopsis glauca, and Schima superba. Using the TAGs to explain the effects of climate change on vegetation distribution on a more regional scale resulted in greater detail than previously used global or continental scale vegetation models.     

Predicting the potential geographic distribution of Thrips palmi in Korea,using the CLIMEX model

Thrips palmi Karny, melon thrips was introduced and first recorded in 1993 in Korea. This species has become a serious pest of vegetable and ornamental crops. The CLIMEX simulation was applied to T. palmi to predict its potential geographic distribution in Korea under the Representative Concentration Pathway (RCP) 8.5 climate change scenario. In the CLIMEX simulation, the ecoclimatic index was calculated, and compared in each simulated year and each simulated location. The map comparisons show good agreements between simulated and present distributions of T. palmi, indicating that the CLIMEX model has promising potential for prediction of future distributions of this species in Korea. In the near future, until the year 2020, all the western and eastern parts of Korea show favorable to marginal suitability for T. palmi populations in the fields. After the year 2040, potential distributions shift from no persistence to favorable for establishment and persistence from coastal to interior regions of the Korean peninsula, except for a north‐eastern interior region which is the northernmost part of a high mountainous (Baekdu‐Daegan) area in Korea. Based on the simulation results, the geographical distribution of T. palmi will expand over its current weather restrictions in the near future under a severe climate change scenario. Thus, pest management measures and strategies should be re‐evaluated in Korea, and should include further studies on interspecific competition and ecosystem changes due to climate changes.     

Impact of landscape predictors on climate change modelling of species distributions: a case study with Eucalyptus fastigata in southern New South Wales,Australia

Aim We consider three questions. (1) How different are the predicted distribution maps when climate‐only and climate‐plus‐terrain models are developed from high‐resolution data? (2) What are the implications of differences between the models when predicting future distributions under climate change scenarios, particularly for climate‐only models at coarse resolution? (3) Does the use of high‐resolution data and climate‐plus‐terrain models predict an increase in the number of local refugia? Location South‐eastern New South Wales, Australia. Methods We developed two species distribution models for Eucalyptus fastigata under current climate conditions using generalized additive modelling. One used only climate variables as predictors (mean annual temperature, mean annual rainfall, mean summer rainfall); the other used both climate and landscape (June daily radiation, topographic position, lithology, nutrients) variables as predictors. Predictions of the distribution under current climate and climate change were then made for both models at a pixel resolution of 100 m. Results The model using climate and landscape variables as predictors explained a significantly greater proportion of the deviance than the climate‐only model. Inclusion of landscape variables resulted in the prediction of much larger areas of existing optimal habitat. An overlay of predicted future climate on the current climate space indicated that extrapolation of the statistical models was not occurring and models were therefore more robust. Under climate change, landscape‐defined refugia persisted in areas where the climate‐only model predicted major declines. In areas where expansion was predicted, the increase in optimal habitat was always greater with landscape predictors. Recognition of extensive optimal habitat conditions and potential refugia was dependent on the use of high‐resolution landscape data. Main conclusions Using only climate variables as predictors for assessing species responses to climate change ignores the accepted conceptual model of plant species distribution. Explicit statements justifying the selection of predictors based on ecological principles are needed. Models using only climate variables overestimate range reduction under climate change and fail to predict potential refugia. Fine‐scale‐resolution data are required to capture important climate/landscape interactions. Extrapolation of statistical models to regions in climate space outside the region where they were fitted is risky.     

Modelling species distributions to predict areas at risk of invasion by the exotic aquatic New Zealand mudsnail Potamopyrgus antipodarum (Gray 1843)

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Evaluation of the spatial distribution of Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) in South Korea combining climate and host plant distribution

Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), a global forest pest, has a potential to damage forests in South Korea, requiring an effective tool for evaluating its potential distribution. This study aimed to evaluate the spatial distribution of A. glabripennis in South Korea by simultaneously considering climate and host plants. Climatic suitability was firstly evaluated using a CLIMEX model; then, it was combined with the areal distribution of host plants using a simple mathematical formulation. We finally projected the spatial distribution of A. glabripennis onto the map of administrative districts to identify hazardous areas to watch. As a result, the developed model predicted that over 40% of areas in South Korea could be exposed to A. glabripennis damage, and most of them were located in mountainous areas with abundant host plants. In addition, climatic suitability was higher in coastal areas, which was different than a previous record of A. glabripennis occurrence, while the prediction by a comprehensive model was consistent with the record. In conclusion, the model including both climate and host plant occurrence was more reliable than the model which only included climate, and could provide useful data for determining areas for monitoring and control.     

Climate-based ensemble modelling to evaluate the global distribution of Anoplophora glabripennis (Motschulsky)

1. Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) is a forest pest that damages a wide range of trees in areas where it has recently been introduced, demanding a proactive evaluation of its possible future distribution.
2. This study aimed to project the potential distribution of A. glabripennis using species distribution modelling and constructed an ensemble map for evaluating global risk areas.
3. We used CLIMEX and MaxEnt to evaluate the potential distribution of A. glabripennis as a function of current and future climates.
4. The results showed that the models predicted a high probability of A. glabripennis distribution where this species is currently found, and the suitable climate was shifted northward due to climate change.
5. The projected area differed between the models because of different modelling algorithm and climate change scenario; thus, an ensemble map projecting the consensus areas from two models was constructed to identify the risk areas that corresponded to the eastern United States, Europe, and native countries, Korea and China, and nearby Japan.
6. From the perspective of ensemble modelling for evaluating species distributions with reduced uncertainties, this study will enhance the model reliability for defining areas at risk of A. glabripennis occurrence.

     

The potential global distribution of the Bronze bug Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae)

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Accommodating scenarios of climate change and management in modelling the distribution of the invasive tree Schinus molle in South Africa

Determining the potential range of invasive alien species under current conditions is important. However, we also need to consider future distributions under scenarios of climate change and different management interventions when formulating effective long‐term intervention strategies. This paper combines niche modelling and fine‐scale process‐based modelling to define regions at high risk of invasion and simulate likely dynamics at the landscape scale. Our study species is Schinus molle (Peruvian pepper tree; Anacardiaceae), a native of central South America, introduced to South Africa in about 1850 where it was widely planted along roads. Localities of planted and naturalized trees were mapped along 5380 km of roads – a transect that effectively samples a large part of western South Africa. Correlative modelling was used to produce profiles of present and future environmental conditions characterizing its planted and naturalized ranges. A cellular‐automata simulation model was used to estimate the dynamics of S. molle under future climates and different management scenarios. The overall potential range of S. molle in the region is predicted to shrink progressively with predicted climate change. Some of the potential range of S. molle defined based on current conditions (including areas where it is currently highly invasive) is likely to become less favourable. The species could persist where it is well established long after conditions for recruitment have deteriorated. Some areas where the species is not widely naturalized now (notably the fynbos biome) are likely to become more favourable. Our modelling approach allows for the delineation of areas likely to be invaded in future by considering a range of factors at different scales that mediate the interplay of climatic variables and other drivers that define the dimensions of human intervention such as distance from planted trees and the density of planted plants, both of which affect propagule pressure.     

The impacts of climate change on the wintering distribution of an endangered migratory bird

There is now ample evidence of the effects of anthropogenic climate change on the distribution and abundance of species. The black-faced spoonbill (Platalea minor) is an endangered migratory species and endemic to East Asia. Using a maximum entropy approach, we predicted the potential wintering distribution for spoonbills and modeled the effects of future climate change. Elevation, human influence index and precipitation during the coldest quarter contributed most to model development. Five regions, including western Taiwan, scattered locations from eastern coastal to central mainland China, coastal areas surrounding the South China Sea, northeastern coastal areas of Vietnam and sites along the coast of Japan, were found to have a high probability of presence and showed good agreement with historical records. Assuming no limits to the spread of this species, the wintering range is predicted to increase somewhat under a changing climate. However, three currently highly suitable regions (northeastern Vietnam, Taiwan and coastal areas surrounding the South China Sea) may face strong reductions in range by 2080. We also found that the center of the predicted range of spoonbills will undergo a latitudinal shift northwards by as much as 240, 450, and 600 km by 2020, 2050 and 2080, respectively. Our findings suggest that species distribution modeling can inform the current and future management of the black-faced spoonbill throughout Asia. It is clear that a strong international strategy is needed to conserve spoonbill populations under a changing climate.     

Suitable areas for the invasion expansion of Xylocopa bees in South America

The introduction of exotic species into native ecosystems can be a cause for concern when those species are invasive. Invasive species cause ecological problems and have socio-cultural impacts on human health and the economy; for example, invasive bees may negatively impact their introduced ecosystem by spreading diseases or outcompeting native pollinators. Xylocopa spp. bees are diverse and distributed throughout the Neotropics. However, Xylocopa augusti (Lepeletier, 1841) and Xylocopa splendidula (Lepeletier, 1841) are not native to Mediterranean Chile. This study aimed to evaluate the invasive potential of these exotic species and predict the potential macroecological effects of their invasions. We also aimed to pinpoint possible distributions for these species throughout South America. We correlated biogeographic occurrence data with climatic variables for each species to model their potential distribution in both current and future scenarios. The models provide strong evidence that both species are changing their distributions: their ranges are expanding towards western South America, particularly Bolivia, Chile and Peru. We demonstrate an increase in niche overlap between these species and show there are new geographic areas vulnerable to the establishment of these invasive bees under current and future climate conditions. These data suggest that these bees may adapt their geographic distribution as the climate changes and pose a threat to native pollinators in new geographic areas.     

The distribution of cultivated species of Porophyllum (Asteraceae) and their wild relatives under climate change

The geographic distribution of plant species is already being affected by climate change. Cropping patterns of edible plant species and their wild relatives will also be affected, making it important to predict possible changes to their distributions in the future. Currently, species distribution models are valuable tools that allow the estimation of species’ potential distributions, in the recent past as well as during other time spans for which climate data have been obtained. With the aim of evaluating how species distributions respond to current and future climate changes, in this work species distribution models were generated for two cultivated species of the Porophyllum genus (Asteraceae), known commonly as ‘pápalos' or ‘pápaloquelites', as well as their Mexican wild relatives, at five points in time (21,000 years ago, present, 2020, 2050, and 2080). Using a database of 1442 entries for 16 species of Porophyllum and 19 environmental variables, species distribution models were constructed for each time period using the Maxent modelling algorithm; those constructed for the future used a severe climate change scenario. The results demonstrate contrasting effects between the two cultivated species; for P. linaria, the future scenario suggests a decrease in distribution area, while for P. macrocephalum distribution is predicted to increase. Similar trends are observed in their wild relatives, where 11 species will tend to decrease in distribution area, while three are predicted to increase. It is concluded that the most important agricultural areas where the cultivated species are grown will not be greatly affected, while the areas inhabited by the wild species will. However, while the results suggest that climate change will affect the distribution of the cultivated species in contrasting ways, evaluations at finer scales are recommended to clarify the impact within cultivation zones.     

Predicted range expansion of the invasive fire ant, Solenopsis invicta, in the eastern United States based on the VEMAP global warming scenario

The red imported fire ant, Solenopsis invicta Buren, is an invasive pest from South America that currently occupies much of the south‐eastern USA. Global warming is likely to allow range expansion of many invasive species, including S. invicta. We used a dynamic, ecophysiological model of fire ant colony growth coupled with models simulating climate change to predict the potential range expansion of S. invicta in the eastern USA over the next century. The climate change scenario predicted by the Vegetation–Ecosystem Modelling and Analysis Project (VEMAP) was used in our analyses. Our predictions indicate that the habitable area for S. invicta may increase by c. 5% over the next 40–50 years (a northward expansion of 33 ± 35 km). As the pace of global warming is expected to quicken in the latter half of the century, however, the habitable area for S. invicta in 2100 is predicted to be > 21% greater than it currently is (a northward expansion of 133 ± 68 km). Because the black imported fire ant, S. richteri Forel, occupies higher latitudes than S. invicta, the overall area of the eastern USA infested with invasive Solenopsis species could be greater than that estimated here.     

Prediction of climate warming impacts on plant species could be more complex than expected. Evidence from a case study in the Himalaya

Many studies have investigated the possible impact of climate change on the distributions of plant species. In the present study, we test whether the concept of potential distribution is able to effectively predict the impact of climate warming on plant species.Using spatial simulation models, we related the actual (current species distribution), potential (modelled distribution assuming unlimited dispersal) and predicted (modelled distribution accounting for wind-limited seed dispersal) distributions of two plant species under several warming scenarios in the Sagarmatha National Park (Nepal). We found that the two predicted distributions were, respectively, seven and nine times smaller than the potential ones. Under a +3 °C scenario, both species would likely lose their actual and predicted distributions, while their potential distributions would remain partially safe. Our results emphasize that the predicted distributions of plant species may diverge to a great extent from their potential distributions, particularly in mountain areas, and predictions of species preservation in the face of climate warming based on the potential distributions of plant species are at risk of producing overoptimistic projections.We conclude that the concept of potential distribution is likely to lead to limited or inefficacious conservation of plant species due to its excessively optimistic projections of species preservation. More robust strategies should utilize concepts such as “optimal reintroduction”, which maximizes the benefit–cost ratio of conservation activities by limiting reintroduction efforts to suitable areas that could not otherwise be reached by a species; moreover, such strategies maximize the probability of species establishment by excluding areas that will be endangered under future climate scenarios.     

Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America

To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid‐ and high‐latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1–17°S and 64–78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high‐elevation oligotrophic lakes, will likely see range contraction under future anthropogenic‐induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra, will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio‐indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes.     

Climate-driven range dynamics of the freshwater limpet, Ancylus fluviatilis (Pulmonata, Basommatophora)

Aim Our aim was to understand the processes that have shaped the present‐day distribution of the freshwater limpet Ancylus fluviatilis sensu stricto in order to predict the consequences of global climate change for the geographical range of this species. Location North‐western Europe. Methods We sampled populations of A. fluviatilis sensu stricto over the entire range of the species (north‐western Europe) and sequenced 16S ribosomal RNA (16S) and cytochrome oxidase subunit I (COI) mitochondrial fragments to perform phylogenetic and phylogeographical analyses. Climatic niche modelling allowed us to infer the climatic preferences of the species. A principal components analysis identified the most important climatic factors explaining the actual range of A. fluviatilis. We also identified which climatic factor was the most limiting at range margins, and predicted the species’ geographical range under a climate change scenario [Community Climate Model 3 (CCM3)]. Results By means of the phylogeographical analysis, we infer that A. fluviatilis sensu stricto occupied northern refuges during the Last Glacial Maximum. We show that the climatic preferences of Baltic populations are significantly different from those of Central European populations. The projection of the occupied area under the CCM3 climate model predicts a moderate poleward shift of the northern range limits, but a dramatic loss of areas currently occupied, for instance in northern Germany and in southern Great Britain. Main conclusions The post‐glacial range dynamics of A. fluviatilis are not governed by niche conservatism. Therefore, we must be cautious about bioclimatic model predictions: the expected impact of climate change could be tempered by the adaptive potential this species has already shown in its evolutionary history. Thus, modelling approaches should rather be seen as conservative forecasts of altered species ranges as long as the adaptive potential of the organisms in question cannot be predicted.     

Geographical distribution of Phagocata vivida in the Far East

Phagocata vivida (Ijima et Kaburaki, 1916) is common in cold-water habitats in mountainous and hilly regions in Japan; in Northern Japan it occurs in lowland areas. Comparative studies of the material from South Korea and Primorskiy in Northeast Siberia, Russia, show that Ph. vivida is distributed widely in these geographic areas. Phagocata miyadii Okugawa, 1939, reported from North Korea and Northeastern China is a synonym of Ph vivida. Geographical distribution of this species in the Japanese Islands now becomes very clear. Judging by its geographical and vertical distributions, the species probably is a preglacial faunal element that entered Japan by the northern route to Old Honshû Island along the coast of the Old Sea of Japan.     

Range reshuffling: Climate change,invasive species,and the case of Nothofagus forests in Aotearoa New Zealand

Aim

The impact of climate change on forest biodiversity and ecosystem services will be partly determined by the relative fortunes of invasive and native forest trees under future conditions. Aotearoa New Zealand has high conservation value native forests and one of the world's worst invasive tree problems. We assess the relative effects of habitat redistribution on native Nothofagus and invasive conifer (Pinaceae) species in New Zealand as a case study on the compounding impacts of climate change and tree invasions.

Location

Aotearoa New Zealand.

Methods

We use species distribution models (SDMs) to predict the current and future distribution of habitat for five native Nothofagus species and 13 invasive conifer species under two 2070 climate scenarios. We calculate habitat loss/gain for all species and examine overlap between the invasive and native species now and in future.

Results

Most species will lose habitat overall. The native species saw large changes in the distribution of habitat with extensive losses in North Island and gains mostly in South Island. Concerningly, we found that most new habitat for Nothofagus was also suitable for at least one invasive species. However, there were refugia for the native species in the wetter parts of the climate space.

Main Conclusion

If the predicted changes in habitat distribution translate to shifts in forest distribution, it would cause widespread ecological disruption. We discuss how acclimation, adaptation and biotic interactions may prevent/delay some changes. But we also highlight that the poor establishment capacity of Nothofagus, and the contrasting ability of the conifers to invade, will present persistent conservation challenges in areas of both new habitat and forest retreat. Pinaceae are problematic invaders globally, and our results highlight that control of invasions and active native forest restoration will likely be key to managing forest biodiversity under future climates.     

孑遗植物长苞铁杉(Tsuga longibracteata)分布格局对未来气候变化的响应

长苞铁杉(Tsuga longibracteata)是中国特有的珍贵树种,不仅对研究裸子植物的系统发育、古生态和古气候具有重要作用,而且该树种具有造林、用材和药用等方面的较高价值。研究长苞铁杉在气候变化下的分布格局变化是制定其保护和可持续利用的重要基础。采用最大熵模型(MaxEnt),结合不同时期(当前、2050年和2070年)和不同二氧化碳排放情境下(RCP2.6和RCP8.5)的气候因子变量,探讨气候变化与物种地理分布格局的关系,预测长苞铁杉的潜在分布区变迁。本研究考虑了空间约束对物种分布的限制作用,构建了气候因子预测模型(C)和气候+空间约束因子预测模型(C+S)分别进行潜在分布区预测,比较其结果差异。结果显示,最干月降水量和温度年较差是影响长苞铁杉地理分布的主导气候因子,空间约束因子对长苞铁杉未来的地理分布有重要影响。随时间年限增加,长苞铁杉总潜在适生区面积降低,特别是中高等级的适生区面积有不同程度地减少,分布范围总体向北移动,这些变化趋势在RCP8.5情境下更加突出。这一结果表明未来气候变化会导致长苞铁杉种群分布范围收缩和生境适宜度下降,加剧其受胁程度。加入空间约束因子后,C+S模型的预测精度更高,结果更符合长苞铁杉的迁移、扩散特性。长苞铁杉未来的核心分布区仍位于现存的湘、桂、黔结合部,表明其具有"原地避难"的特性,应进一步加强对现有野生资源的保护。渝、川、鄂结合部的大巴山等地区是未来气候变化下长苞铁杉的理论分布区域,可作为长苞铁杉应对未来气候变化的引种地区,应提早进行人工引种、栽培等前期研究。研究结果可为气候变化背景下长苞铁杉的保护、物种迁地保存和可持续管理提供科学依据,也可为准确预测濒危、珍稀植物的地理分布范围提供方法参考。     

Oviposition and reproductive performance of a generalist parasitoid (Trichogramma pretiosum) exposed to host species that differ in their physical characteristics

The response of generalist egg parasitoids to alternative natural hosts that are present simultaneously is not well known. We investigated the behavior of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) in relation to two field hosts Helicoverpa armigera Hübner and Spodoptera litura Fabricius, in choice and no choice tests. We quantified the effects of natal host species and post-emergence adult age on the oviposition preference of the parasitoids. H. armigera eggs were consistently preferred over S. litura eggs, regardless of the natal host and adult age. When only S. litura eggs were available as hosts, they were parasitized at statistically similar rates to H. armigera eggs (average of 17 ± 2.7 vs. 13 ± 3.0, H. armigera to S. litura). The adult lifespan and lifetime fecundity of T. pretiosum were variable but were affected by natal host species and/or host species to which they were exposed. Mean lifespan and fecundity of parasitoids that had developed in H. armigera eggs and were exposed to H. armigera eggs for oviposition were 13.9 ± 1.8 days and 98.7 ± 11.0 adult offspring. By contrast, those that developed in S. litura eggs and were exposed to S. litura eggs for oviposition lived for 7 ± 0.9 days and produced 53.8 ± 8.0 adult offspring. The ovigeny index (OI) was significantly lower in the parasitoids exposed to H. armigera eggs than in those exposed to S. litura eggs, regardless of the natal host, indicating that H. armigera eggs sustain the adult parasitoids better than S. litura eggs. These results are used to predict parasitoid behavior in the field when both hosts are available.