scholarly journals Slaves of the environment: the movement of herbivorous insects in relation to their ecology and genotype

1999 ◽  
Vol 354 (1388) ◽  
pp. 1479-1495 ◽  
Author(s):  
Hugh D. Loxdale ◽  
Gugs Lushai
Keyword(s):  
Spatial Scale ◽  
Large Population ◽  
Insect Population ◽  
Insect Species ◽  
Herbivorous Insect ◽  
Suitable Habitat ◽  
Long Distance ◽  
Flight Behaviour ◽  
Vast Number ◽  
Insect Movement

The majority of insect species do not show an innate behavioural migration, but rather populations expand into favourable new habitats or contract away from unfavourable ones by random changes of spatial scale. Over the past 50 years, the scientific fascination with dramatic long–distance and directed mass migratory events has overshadowed the more universal mode of population movement, involving much smaller stochastic displacement during the lifetime of the insects concerned. This may be limiting our understanding of insect population dynamics. In the following synthesis, we provide an overview of how herbivorous insect movement is governed by both abiotic and biotic factors, making these animals essentially ‘slaves of their environment’. No displaced insect or insect population can leave a resource patch, migrate and flourish, leaving descendants, unless suitable habitat and/or resources are reached during movement. This must have constrained insects over geological time, bringing about species–specific adaptation in behaviour and movements in relation to their environment at a micro– and macrogeographical scale. With insects that undergo long–range spatial displacements, e.g. aphids and locusts, there is presumably a selection against movement unless overruled by factors, such as density–dependent triggering, which cause certain genotypes within the population to migrate. However, for most insect species, spatial changes of scale and range expansion are much slower and may occur over a much longer time–scale, and are not innate (nor directed). Ecologists may say that all animals and plants are figuratively speaking ‘slaves of their environments’, in the sense that their distribution is defined by their ecology and genotype. But in the case of insects, a vast number must perish daily, either out at sea or over other hostile habitats, having failed to find suitable resources and/or a habitat on which to feed and reproduce. Since many are blown by the vagaries of the wind, their chances of success are serendipitous in the extreme, especially over large distances. Hence, the strategies adopted by mass migratory species (innate pre–programmed flight behaviour, large population sizes and/or fast reproduction), which improve the chances that some of these individuals will succeed. We also emphasize the dearth of knowledge in the various interactions of insect movement and their environment, and describe how molecular markers (protein and DNA) may be used to examine the details of spatial scale over which movement occurs in relation to insect ecology and genotype.

scholarly journals Why are there not more herbivorous insect species?

2021 ◽  
Vol 67 (2) ◽  
pp. 119-160
Author(s):  
Tibor Jermy ◽  
Árpád Szentesi
Keyword(s):  
Life Histories ◽  
Ecological Factors ◽  
Host Specialization ◽  
Insect Species ◽  
Herbivorous Insect ◽  
Vast Number ◽  
Physiological Limits ◽  
Wide Range ◽  
Plant Allelochemicals ◽  
Insect Species Richness

Insect species richness is estimated to exceed three million species, of which roughly half is herbivorous. Despite the vast number of species and varied life histories, the proportion of herbivorous species among plant-consuming organisms is lower than it could be due to constraints that impose limits to their diversification. These include ecological factors, such as vague interspecific competition; anatomical and physiological limits, such as neural limits and inability of handling a wide range of plant allelochemicals; phylogenetic constraints, like niche conservatism; and most importantly, a low level of concerted genetic variation necessary to a phyletic conversion. It is suggested that diversification ultimately depends on what we call the intrinsic trend of diversification of the insect genome. In support of the above, we survey the major types of host-specificity, the mechanisms and constraints of host specialization, possible pathways of speciation, and hypotheses concerning insect diversification.

scholarly journals Long-term shifts in abundance of (migratory) crop-feeding and beneficial insect species in northeastern Asia

2020 ◽  
Vol 93 (2) ◽  
pp. 583-594 ◽  
Author(s):  
Jianglong Guo ◽  
Xiaowei Fu ◽  
Shengyuan Zhao ◽  
Xiujing Shen ◽  
Kris A. G. Wyckhuys ◽  
...  
Keyword(s):  
Capture Rate ◽  
Early Warning Systems ◽  
Insect Species ◽  
Eastern Asia ◽  
Long Distance ◽  
Species Complexes ◽  
Migration Dynamics ◽  
Rate Of Decline ◽  
Trap Catches

AbstractVast numbers of insects annually engage in trans-latitudinal migration and thereby impact structure and functioning of natural and man-made ecosystems. In eastern Asia, long-distance migration has historically been studied for single insect species rather than diverse species complexes. Here, we assessed migration dynamics of multiple economically important migratory species on an island in the Bohai Strait, China. Drawing upon 15-year trapping records of > 2.5 million specimens, we unveil inter- and intra-annual shifts in the species composition and abundance of migrant individuals. Migrants belonged to 9 orders and 36 families, primarily consisting of Lepidoptera (79% individuals), Odonata (8%), and Coleoptera (4%). Seven crop-feeding noctuids, e.g., Helicoverpa armigera (Hübner), Mythimna separata (Walker), represented 54% of the total trapping records. Trap catches exhibited marked seasonal variation, with the highest capture rate during early fall. Yearly abundance of migratory noctuids was coupled with that of their associated natural enemies. Although overall trap catches did not decrease over the monitoring period, the entire order of Odonata experienced a 14.1% annual rate of decline. Furthermore, 19 out of 108 species exhibited a progressively declining abundance over time, including the cosmopolitan cutworm Agrotis ipsilon (Hufnagel) and the insectivorous dragonfly Pantala flavescens Fabricius. Our work provides unprecedented insights into insect migration dynamics in eastern Asia, helps fine-tune forecasting and early-warning systems of crop pests, and thereby guides integrated pest management within local agro-landscapes. Also, a long-term tracking of migrant insect populations can shine light on the fate of (insect-mediated) ecosystem services and trophic dynamic processes at a macroscale.

scholarly journals A review of the status of the Green Peafowl Pavo muticus and recommendations for future action

1998 ◽  
Vol 8 (4) ◽  
pp. 331-348 ◽  
Author(s):  
P. J. K. McGowan ◽  
J. W. Duckworth ◽  
Wen Xianji ◽  
B. Van Balen ◽  
Yang Xiaojun ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Action Plan ◽  
Large Population ◽  
Peninsular Malaysia ◽  
Suitable Habitat ◽  
Conservation Action ◽  
North East ◽  
Ecological Requirements ◽  
The Status ◽  
Green Peafowl

SummaryThe Green Peafowl has undergone a substantial decline throughout East Asia since the turn of the century and is now reported only from a few widely scattered localities in several countries. Its plight was highlighted in the IUCN Pheasant Action Plan where it was one of the highest priorities for conservation action. Recent surveys have clarified its status and distribution in at least part of several range countries and there is patchy information from elsewhere in its range. The current knowledge of the species was reviewed at a workshop in Malaysia in autumn 1997 at which representatives from most key countries were present. The species is extinct in Peninsular Malaysia, and almost lost from Bangladesh and north-east India. There is one large population remaining in Thailand and the species is thought to be in danger of extinction in Laos. China and Indonesia hold mostly small and scattered populations although the latter does contain two large protected populations. The status in Myanmar and Cambodia is unknown, although the presence of large tracts of apparently suitable habitat in eastern Cambodia suggest that this area may hold the largest populations of the species. Conservation recommendations fall into four categories: a strategic review, assessing status and understanding ecological requirements, investigating the human-Green Peafowl relationship and considering the possibility of reintroducing the species where appropriate.

Contrasting effects of sewage sludge and commercial fertilizer on egg to adult development of two herbivorous insect species

Ecotoxicology ◽  
1994 ◽  
Vol 3 (2) ◽  
pp. 94-109 ◽  
Author(s):  
Kirk J. Larsen ◽  
Amy L. Litsch ◽  
Susan R. Brewer ◽  
Douglas H. Taylor
Keyword(s):  
Sewage Sludge ◽  
Adult Development ◽  
Insect Species ◽  
Herbivorous Insect ◽  
Commercial Fertilizer

scholarly journals Diet breadth and its relationship with genetic diversity and differentiation: the case of southern beech aphids (Hemiptera: Aphididae)

2004 ◽  
Vol 94 (3) ◽  
pp. 219-227 ◽  
Author(s):  
C. Gaete-Eastman ◽  
C.C. Figueroa ◽  
R. Olivares-Donoso ◽  
H.M. Niemeyer ◽  
C.C. Ramírez
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Diet Breadth ◽  
Aphid Species ◽  
Insect Species ◽  
Herbivorous Insect ◽  
Genetic Structuring ◽  
Closely Related Species ◽  
Single Host ◽  
Southern Beech

AbstractHerbivorous insect species with narrow diet breadth are expected to be more prone to genetic differentiation than insect species with a wider diet breadth. However, a generalist can behave as a local specialist if a single host-plant species is locally available, while a specialist can eventually behave as a generalist if its preferred host is not available. These problems can be addressed by comparing closely related species differing in diet breadth with overlapping distributions of insect and host populations. In this work, diet breadth, genetic diversity and population differentiation of congeneric aphid species from southern beech forests in Chile were compared. While at the species level no major differences in genetic diversity were found, a general trend towards higher genetic diversity as diet breadth increased was apparent. The aphid species with wider diet breadth, Neuquenaphis edwardsi (Laing), showed the highest genetic diversity, while the specialist Neuquenaphis staryi Quednau & Remaudière showed the lowest. These differences were less distinct when the comparisons were made in the same locality and over the same host. Comparison of allopatric populations indicates that genetic differentiation was higher for the specialists, Neuquenaphis similis Hille Ris Lambers and N. staryi, than for the generalist N. edwardsi. Over the same host at different locations, genetic differentiation among populations of N. edwardsi was higher than among populations of N. similis. The results support the assumption that specialists should show more pronounced genetic structuring than generalists, although the geographical distribution of host plants may be playing an important role.

scholarly journals Metabolic constraints on long-distance migration in birds

1996 ◽  
Vol 199 (1) ◽  
pp. 57-64 ◽  
Author(s):  
M Klaassen
Keyword(s):  
Water Balance ◽  
Water Loss ◽  
Physiological Stress ◽  
Plasma Osmolality ◽  
Large Species ◽  
Long Distance ◽  
Flight Behaviour ◽  
Flight Range ◽  
Ecological Barriers ◽  
Balance Problems

The flight range of migrating birds depends crucially on the amount of fuel stored by the bird prior to migration or taken up en route at stop-over sites. However, an increase in body mass is associated with an increase in energetic costs, counteracting the benefit of fuel stores. Water imbalance, occurring when water loss exceeds metabolic water production, may constitute another less well recognised problem limiting flight range. The main route of water loss during flight is via the lungs; the rate of loss depends on ambient temperature, relative humidity and ventilatory flow and increases with altitude. Metabolite production results in an increased plasma osmolality, also endangering the proper functioning of the organism during flight. Energetic constraints and water-balance problems may interact in determining several aspects of flight behaviour, such as altitude of flight, mode of flight, lap distance and stop-over duration. To circumvent energetic and water-balance problems, a bird could migrate in short hops instead of long leaps if crossing of large ecological barriers can be avoided. However, although necessitating larger fuel stores and being more expensive, migration by long leaps may sometimes be faster than by short hops. Time constraints are also an important factor in explaining why soaring, which conserves energy and water, occurs exclusively in very large species: small birds can soar at low speeds only. Good navigational skills involving accurate orientation and assessment of altitude and air and ground speed assist in avoiding physiological stress during migration.

scholarly journals Hawkmoth Pollination Facilitates Long-distance Pollen Dispersal and Reduces Isolation Across a Gradient of Land-use Change

2019 ◽  
Vol 104 (3) ◽  
pp. 495-511 ◽  
Author(s):  
Krissa A. Skogen ◽  
Rick P. Overson ◽  
Evan T. Hilpman ◽  
Jeremie B. Fant
Keyword(s):  
Land Use ◽  
Gene Flow ◽  
Habitat Fragmentation ◽  
Land Use Change ◽  
Pollen Dispersal ◽  
Suitable Habitat ◽  
Long Distance Dispersal ◽  
Effective Population ◽  
Long Distance ◽  
Genetic Diversity And Structure

Land-use change is among the top drivers of global biodiversity loss, which impacts the arrangement and distribution of suitable habitat for species. Population-level effects include increased isolation, decreased population size, and changes to mutualistic and antagonistic interactions. However, the extent to which species are impacted is determined by life history characteristics including dispersal. In plants, mating dynamics can be changed in ways that can negatively impact population persistence if dispersal of pollen and/or seed is disrupted. Long-distance dispersal has the potential to buffer species from the negative impacts of land-use change. Biotic vectors of long-distance dispersal have been less frequently studied, though specific taxa are known to travel great distances. Here, we describe population genetic diversity and structure in a sphingophilous species that is experiencing habitat fragmentation through land-use change, Oenothera harringtonii W. L. Wagner, Stockh. & W. M. Klein (Onagraceae). We use 12 nuclear and four plastid microsatellite markers and show that pollen dispersal by hawkmoths drives high gene flow and low population differentiation despite a range-wide gradient of land-use change and habitat fragmentation. By separating the contributions of pollen and seed dispersal to gene flow, we show that most of the genetic parameters are driven by hawkmoth-facilitated long-distance pollen dispersal, but populations with small, effective population sizes experience higher levels of relatedness and inbreeding. We discuss considerations for conservation efforts for this and other species that are pollinated by long-distance dispersers.

scholarly journals Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds

2011 ◽  
Vol 278 (1721) ◽  
pp. 3074-3080 ◽  
Author(s):  
Thomas Alerstam ◽  
Jason W. Chapman ◽  
Johan Bäckman ◽  
Alan D. Smith ◽  
Håkan Karlsson ◽  
...  
Keyword(s):  
Passerine Birds ◽  
Long Distance ◽  
Flight Behaviour ◽  
Preferred Direction ◽  
Migration Strategies ◽  
Migrant Birds ◽  
Nocturnal Migration ◽  
Self Powered ◽  
Migratory Strategies ◽  
Air Streams

Vast numbers of insects and passerines achieve long-distance migrations between summer and winter locations by undertaking high-altitude nocturnal flights. Insects such as noctuid moths fly relatively slowly in relation to the surrounding air, with airspeeds approximately one-third of that of passerines. Thus, it has been widely assumed that windborne insect migrants will have comparatively little control over their migration speed and direction compared with migrant birds. We used radar to carry out the first comparative analyses of the flight behaviour and migratory strategies of insects and birds under nearly equivalent natural conditions. Contrary to expectations, noctuid moths attained almost identical ground speeds and travel directions compared with passerines, despite their very different flight powers and sensory capacities. Moths achieved fast travel speeds in seasonally appropriate migration directions by exploiting favourably directed winds and selecting flight altitudes that coincided with the fastest air streams. By contrast, passerines were less selective of wind conditions, relying on self-powered flight in their seasonally preferred direction, often with little or no tailwind assistance. Our results demonstrate that noctuid moths and passerines show contrasting risk-prone and risk-averse migratory strategies in relation to wind. Comparative studies of the flight behaviours of distantly related taxa are critically important for understanding the evolution of animal migration strategies.

Dispersal of fig pollinators in Asian tropical rain forests

2006 ◽  
Vol 22 (6) ◽  
pp. 631-639 ◽  
Author(s):  
Rhett D. Harrison ◽  
Jean-Yves Rasplus
Keyword(s):  
Species Composition ◽  
Peninsular Malaysia ◽  
Long Distance Dispersal ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Long Distance ◽  
Temporal And Spatial Variation ◽  
Flight Behaviour ◽  
Species Overlap ◽  
Temporal And Spatial

Fig pollinators (Agaonidae, Chalcioidea) lay their eggs in fig inflorescences (Ficus, Moraceae). Reproductive success for both partners is thus largely dependent on the dispersal of these tiny wasps. Some are known to cover substantial distances (> 10 km) using wind above the canopy. However, fig ecology is extremely varied, and hence one might also expect a diversity of pollinator dispersal strategies. We studied fig pollinator dispersal in Sarawak (2001 and 2004) and Peninsular Malaysia (2003). The results indicate substantial differences in dispersal ecology between the pollinators of monoecious and dioecious figs. Monoecious-fig pollinators were common, and species composition and rank abundances were similar between years despite short sampling periods. Substantial temporal and spatial variation in their production is thus smoothed out by long-distance dispersal. Some species whose hosts do not occur at our Sarawak site and are rare throughout Borneo were caught, suggesting exceptionally long-distance dispersal in these species. Conversely, few dioecious-fig pollinators were caught and species overlap between years was low. Dispersal range in many dioecious-fig pollinators may be more restricted. At a finer scale, among genera pollinating monoecious figs we found marked differences in flight behaviour (height and time-of-dispersal). We relate these findings to the ecology of their hosts, and discuss the implications for fig–fig-pollinator coevolution.

Sign in / Sign up

Export Citation Format

Share Document