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Locusts and Grasshoppers: Behavior, Ecology, and Biogeography

Hindawi Publishing Corporation
Volume 2011, Article ID 578327, 4pages
Locusts and Grasshoppers: Behavior, Ecology, and Biogeography
Alexandre Latchininsky,1Gregory Sword,2, 3 Michael Sergeev,4, 5
Maria Marta Cigliano,6and Michel Lecoq7
1Department of Renewable Resources, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
2School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia
3Department of Entomology, Faculty of Ecology and Evolutionary Biology, Heep Building, Texas A&M University, College Station,
TX 77842-2475, USA
4Department of General Biology and Ecology, Novosibirsk State University, 2 Pirogova Street, Novosibirsk 630090, Russia
5Laboratory of Insect Ecology, Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences,
11 Frunze Street, Novosibirsk 630091, Russia
6Division Entomologia, Museo de La Plata, Universidad Nacional de la Plata, Paseo del Bosque S/N,1900 La Plata, Argentina
7CIRAD Bioagresseurs, TA A-106/D, Campus International de Baillarguet, 34398 Montpellier cedex 5, France
Correspondence should be addressed to Alexandre Latchininsky,
Received 27 January 2011; Accepted 27 January 2011
Copyright © 2011 Alexandre Latchininsky et al. This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Locusts and grasshoppers (L&G) (Orthoptera: Caelifera,
Acridoidea) are an essential component of both, healthy, and
disturbed grassland ecosystems. These insects are abundant
in natural and anthropogenic habitats (rangelands, wetlands,
agricultural fields, lawns, etc.). They stimulate plant growth,
participate in nutrient cycling, and play important role
in food chains [15]. Some grasshoppers are proposed as
ecological indicators of ecosystem qualities and ecacy of
ecological networks [6]. On the other hand, when their pop-
ulations grow to catastrophic dimensions, L&G are among
the most devastating enemies of agriculturists. Outbreaks
of locusts such as Schistocerca gregaria (Forsk˚
al, 1775),
Nomadacris septemfasciata (Serville, 1838), Locusta migra-
toria Linnaeus, 1758, Calliptamus italicus (Linnaeus, 1758),
Dociostaurus maroccanus (Thunberg, 1815), Chortoicetes
terminifera (Walker, 1870), and many abundant grasshopper
species continue to occur on all continents except Antarctica
and aect the livelihoods of one in every ten people on Earth.
Such L&G outbreaks are now better controlled and their
frequency and size have been reduced with the application
of preventative strategies [7,8]. However, invasions still
persist. During the outbreak of the Desert locust S. gregaria
in Africa in 2003–2005, over eight million people suered
from severe 80 to 100% crop losses [9]. To combat the
locust swarms, 13 million hectares in 22 countries on three
continents were treated with broad-spectrum neurotoxins.
Such transcontinental operation, including the food aid for
aected population, cost over half a billion US dollars to the
world community [10].
Losses to L&G are not limited to crop and rangeland
destruction. Besides the economic damage and its subse-
quent negative social impact, L&G outbreaks may seriously
alter ecological processes across landscapes (e.g., carbon and
water cycles). The rapid loss of vegetation cover may result
in soil erosion and increased runo.L&Gcanalsodestroy
food sources for many animals and thus aect biodiversity;
such eects may be particularly pronounced in isolated
insular ecosystems [11]. Large-scale L&G control programs
can also aect biodiversity, including that of nontarget
grasshoppers [12]. Despite decades of intensive research,
the mechanisms underlying L&G population dynamics (and
for locusts: phase transformation) are not fully elucidated.
Only recently, significant advances were made in our
understanding of L&G behavior and ecology, particularly
individual and group movement, nutritional requirements,
and biochemical mechanisms underlying the transformation
between solitarious and gregarious locust phases [1315]; see
also review in [16].
Besides the notorious pests, this group of insects includes
many understated rare species which require protection [17
19]. To complicate the picture, following landscape changes
induced by human agricultural activities, some economic
pests may become exceedingly rare [20]. On the other hand,
many orthopteran species benefit from human-induced
landscape changes and increase their abundance [18,21].
Disturbed and new habitats can be important for spreading
and living of some native and alien grasshopper forms
[18,21,22]. At the same time, many of rare grasshopper
species are threatened by anthropogenic influences, such as
overgrazing and ploughing [18]. However, in various areas,
such as temperate Eurasia or in Tropical Madagascar, several
centers of orthopteran diversity and endemism overlap
with areas of frequent L&G outbreaks [2325]. This means
that problems of plant protection and conservation biology
should be solved on the complex basis of a holistic approach.
However, it is hardly ever the case; pests and rare species are
usually studied separately, and their possible relationships are
not explored.
Although the general patterns of grasshopper distribu-
tion are described for dierent regions [2628], the main
factors and processes determining grasshopper diversity
patterns at dierent scales are still under discussion. Impor-
tance of temperatures and precipitation is evident, but the
distribution of many species, populations, and assemblages
could not be explained by macroclimatic factors only [29].
This means that the role of other factors and processes should
be investigated more thoroughly. At a regional level, it is
possible to establish the general pattern of regional biodiver-
sity and explain how the spatial distribution of populations
permits species with various origins and dierent ecological
preferences to coexist [30].
An example of this approach is the opening article for
this special issue of Psyche, in which M. G. Sergeev reviews
distribution patterns of over 130 species of grasshoppers
and their kin in the boreal zone. Grasshoppers and their
relatives occupy there almost exclusively open habitats, such
as meadows, mountain steppes and tundras, clearings, open-
ings, bogs, and stony flood plains. The boreal orthopteroid
assemblages exhibit low species diversity and abundance.
Based on the biogeographic analysis, the author concludes
that relationships between the faunas of the Eurasian and
North American parts of the boreal zone are relatively
Local grasshopper distribution patterns have been dis-
cussed since the beginning of the 20th century. Possible
relationships between grasshopper diversity, plant species
composition, and habitat structure have been discussed for
many decades. The paper of D. H. Branson (second in
this special issue) provides an example of such studies. The
author found these relationships too complicated for simple
explanations. The type, level, strength, and complexity of
these relationships may be determined not only by local but
also by regional patterns. Consequently, to evaluate general
trends in grasshopper diversity one should study all main
regions and ecosystems in the same manner. This idea may
serve as a basis for an ambitious regional study.
The third paper of the special issue is devoted to a
complex terminological issue. Acridologists have used a
variety of terms to describe groups of grasshoppers, includ-
ing assemblage, community, guild, and population. This
terminological diversity has raised the question of whether
one of these descriptors is the correct one. The author, J.
A. Lockwood, argues that a term is correct if it accurately
reflects the conceptual framework of the investigator and
eectively communicates this perspective to others. He
describes the contexts in which the most common terms are
In the next paper, O. Olfert et al. investigate the impact
of climate changes on distribution and relative abundance
of a pest grasshopper of major economic importance in
North America, Melanoplus sanguinipes. Various scenarios
of climatic changes were used to parameterize a bioclimatic
model of this species. Compared to predicted range and
distribution under current climate conditions, model results
indicated that M. sanguinipes would have increased range
and relative abundance in more northern regions of North
America. Conversely, model output predicted that the range
of this crop pest could contract in regions where climate
conditions became limiting. However, some caution has been
expressed by authors. The impact of biotic factors such as
natural enemies should also be considered, and bioclimatic
modeling of grasshopper populations will surely benefit
in the future from a multitrophic approach (host plants-
grasshoppers-natural enemies).
The fifth paper of this special issue by H. Song reviews the
current state-of-the-art regarding locust phase polyphenism
in species other than the two model locusts. Although the
mechanisms of locust phase transformation are relatively
well understood for the Desert locust and the Migratory
locust, they remain largely obscure in nonmodel locust
species. The author found similar density-dependent pheno-
typic plasticity among closely related species. He emphasized
the importance of comparative analyses in understanding the
evolution of locust phase and proposed a phylogeny-based
research framework for future analyses.
In the next paper M. Lecoq et al. present a typology quan-
tifying density-dependent color change in the Red locust
nymphs. This information can contribute to improving
the reliability of the data collected by the National Locust
Centers when surveying this major pest. The authors, in
Madagascar, sampled hoppers from several populations of
dierent density and measured the color of dierent body
parts as categorical variables. They found that color change
is positively correlated with population density. This study
is an important contribution to our knowledge of locust
coloration in the field, for which there is currently a weaker
understanding than that for laboratory populations.
The seventh paper of this special issue by S. O. Ely et al.
discusses the diel behavioral activity patterns of solitarious
Desert locust adults. The authors found that the insects
were more attracted to volatiles from potted Heliotropium
ovalifolium in scotophase than in photophase. The attraction
towards the host plant odors, in both photophase and
scotophase, concurs with previous observations on locust
oviposition preferences near these plants.
Psyche 3
experiments with Beauveria bassiana (Fungi: Ascomycota),
an entomopathogenic fungus that serves as a biological con-
trol agent of Mormon crickets Anabrus simplex Haldeman
(Orthoptera: Tettigoniidae) and other grasshopper pests.
They demonstrated an immune response of infected Mor-
mon crickets and concluded that circulating phenoloxidase
may be an important enzymatic defense against Beauveria
infection, and that it is associated with attempted clearing
of Beauveria blastospores and hyphae from Mormon cricket
Alexandre Latchininsky
Gregory Sword
Michael Sergeev
Maria Marta Cigliano
Michel Lecoq
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... Locust and grasshoppers (Orthoptera, Acridoidea) are essential herbivores in grassland ecosystems worldwide (Latchininsky et al. 2011, Fang et al. 2015. They aid in plant growth and nutrient cycling and play an important part in food chains (Kietzka et al. 2021). ...
... However, locust and grasshopper outbreaks are considered a global problem. They can destroy grasslands and crops and inflict severe economic impacts on crops and rangelands (Hewitt 1977, Gupta 1983, Lockwood and Lockwood 2008, Latchininsky et al. 2011, Lecoq and Cease 2022. A few grasshopper species have been proposed as ecological indicators of ecosystem health as they are susceptible to changes in land use and climate (Marini et al. 2008, Fartmann et al. 2012, Bazelet and Samways 2012, Uchida and Ushimaru 2014. ...
Full-text available
Grasshoppers (Acridoidea, Orthoptera) are the dominant herbivores in grassland ecosystems worldwide. They can increase rangeland productivity by stimulating plant growth and accelerating nutrient cycling. This article presents a comprehensive checklist of grasshoppers in Mongolia. Until then, the available information was very scattered, based on old studies of Mongolian grasshoppers, recorded in a few international catalogues and databases, individual records and research work on agroecosystem communities. However, the available information on the composition of the Orthopteran fauna in Mongolia was sometimes unclear or non-existent and these dubious data were excluded from the present study. In addition, the grasshopper distribution analysis used the standardised personal collection of D. Altanchimeg. We also present a list of grasshoppers, as well as their distribution and abundance, in countries adjacent to Mongolia, such as Russia, China and South Korea. The surveys covered six types of natural zones: high mountain, taiga, forest-steppe, steppe, desert steppe and desert; desert steppe and steppe zones are the most widely distributed. We hope to have contributed significantly to the study of the distribution of grasshopper species in all these natural zones. In this study, a total of three families of Acridoidea belonging to eight subfamilies, 17 tribes, 52 genera and 128 species are reported for the various natural zones. The recorded species belong to eight subfamilies: Gomphocerinae are the most numerous with 56 species recorded, followed by Oedipodinae (51 species), Thrinchinae (nine species), Melanoplinae (six species), Calliptaminae (three species), Dericorythinae, Acridinae, Egnatiinae (one species each).
... Orthopterans are the most common insects in terrestrial grassland ecosystems comprising 29,207 species around the world (Guo et al., 2006;Jonas & Joern, 2007;Latchininsky et al., 2011;Cigliano et al., 2022). Grasshoppers are an excellent ecological and biological indicator of ecosystem qualities and the efficacy of ecological networks (Gebeyehu et al., 2002;Bazelet & Samways, 2011;Bazelet & Samways, 2014;Zhang et al., 2019). ...
... Grasshoppers are an excellent ecological and biological indicator of ecosystem qualities and the efficacy of ecological networks (Gebeyehu et al., 2002;Bazelet & Samways, 2011;Bazelet & Samways, 2014;Zhang et al., 2019). Besides estimating species diversity and abundance (Latchininsky et al., 2011;Mariottini et al., 2013;Sergeev, 2021), they are also one of the causes of significant damage to crops (Begna & Fielding, 2003;Zhang et al., 2019;Dakhel et al., 2020). ...
Full-text available
Previously published works of literature were reviewed to prepare the checklist of grasshoppers under the family Acrididae from Nepal. The present checklist of grasshoppers under the family Acrididae includes 69 species belonging to 41 genera, and 18 tribes with 11 subfamilies. Oedipodinae (17) was the most species-richest subfamily followed by Gomphocerinae (12), Catantopinae (9), Oxyinae (7), Cyrtacanthacridinae (6), Acridinae (6), Eyprepocnemidinae (4), Coptacrinae (3), Hemiacridinae (2), Calliptaminae (2), and Spathosterninae (1). This checklist will be also helpful to forecast outbreaks of grasshopper species and apply appropriate management approaches. Keywords: Acrididae , Checklist , Distribution , Diversity , Nepal , Oriental
... Locusts are grasshoppers in the family Acrididae which are characterized by the so-called phase polyphenism . At low density, the locusts behave as solitarious individuals and are an important part of their ecosystem (Cullen et al., 2017;Latchininsky et al., 2011). The phase change is initiated by a combination of different ecological conditions which benefit increasing locust population. ...
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Negative impacts on agricultural activities by different locust species are well documented and have always been one of the major threats to food security and livelihoods, especially for local communities. Locust management and control have led to less frequent and intense plagues and outbreaks worldwide. However, political insecurity and armed conflicts affect locust management, and can as well as changing climate, and land use management contribute to new outbreaks. In the context of the increasing world population and higher demand for agricultural production, locust pests will remain of high concern. Geospatial and remote sensing data have become an important source of information for different applications within locust research and management. However, there is still a gap between available information and actual practical usage. In this study, we demonstrate the importance of geospatial and remote sensing data and how this information can be prepared for a straightforward application for stakeholders. For this purpose, we use the h3-hexagonal hierarchical geospatial indexing system to simplify and structure spatial information into standardized hexagon units. The presented concept provides decision makers and ground teams with a simplified information database that contains area-wide information over time and space and can be used without detailed geospatial knowledge and background. The concept is designed for the use case of Italian locust management in the Pavlodar region (Kazakhstan) and based on actual practices. It can be extrapolated to any other study area or species of interest. Our results underline the importance of actual land management on locust presence. Up-to-date land management information can be derived from time-series analyses of remote sensing data. Furthermore, essential meteorological data are used to generate locust-specific climatic characteristics within the h3-system. Within this system, areal prioritizing for locust management can be achieved based on the included spatial information and experience from ongoing practices.
... Similar to the wingless aphids, which stay on their maternal plant for the extent of damage (Gia and . In contrast, the gregarious desert locusts will swarm and travel around hundreds of miles and are responsible for complete crop damage (Latchininsky et al., 2011). The crop pests crossing over the different crops and natural vegetation or living between complex heterogenic land uses are generally exposed to a broader range of macro and microclimates. ...
The improvement and application of pest models to predict yield losses is still a challenge for the scientific community. However, pest models were targeted chiefly towards scheduling scouting or pesticide applications to deal with pest infestation. Thysanoptera (thrips) significantly impact the productivity of many economically important crops worldwide. Until now, no comprehensive study is available on the global distribution of pest thrips, as well as on the extent of cropland vulnerability worldwide. Further, nothing is known about the climate change impacts on these insects. Thus the present study was designed to map the global distribution and quantify the extent of cropland vulnerability in the present and future climate scenarios using data of identified pest thrips within the genus, i.e., Thrips, Frankliniella, and Scirtothrips. Our found significant niche contraction under the climate change scenarios and thrips may reside primarily in their thermal tolerance thresholds. About 3,98,160 km2 of cropland globally was found to be affected in the present scenario. However, it may significantly reduce to 5530 Km2 by 2050 and 1990 km2 by 2070. Further, the thrips distribution mostly getting restricted to Eastern North America, the North-western of the Indian sub-continent, and the north of Europe. Among all realms, thrips may lose ground in the Indo-Malayan realm at the most and get restricted to only 27 out of 825 terrestrial ecoregions. The agrarian communities of the infested regions may get benefit if these pests get wiped out, but on the contrary, we may lose species diversity. Moreover, the vacated niche may attract other invasive species, which may seriously impact the species composition and agricultural productivity. The present study findings can be used in making informed decisions about prioritizing future economic and research investments on the thrips in light of anticipated climate change impacts.
... The characterization of the land surface, specifically focusing on habitats of different locust pests, has been part of research efforts to support preventive locust management [42][43][44][45][46][47][48][49]. Abandoned and fallow fields or untilled land can provide ideal breeding habitats for some locust species, thus increasing the possibility of a population upsurge and outbreaks [3,11,41,[50][51][52]. On the contrary, regular mechanical treatment of fields and pasture (plowing) usually destroys locust eggs and hence contributes to population decrease [53]. ...
Full-text available
The Moroccan locust has been considered one of the most dangerous agricultural pests in the Mediterranean region. The economic importance of its outbreaks diminished during the second half of the 20th century due to a high degree of agricultural industrialization and other human-caused transformations of its habitat. Nevertheless, in Sardinia (Italy) from 2019 on, a growing invasion of this locust species is ongoing, being the worst in over three decades. Locust swarms destroyed crops and pasture lands of approximately 60,000 ha in 2022. Drought, in combination with increasing uncultivated land, contributed to forming the perfect conditions for a Moroccan locust population upsurge. The specific aim of this paper is the quantification of land cover land use (LCLU) influence with regard to the recent locust outbreak in Sardinia using remote sensing data. In particular, the role of untilled, fallow, or abandoned land in the locust population upsurge is the focus of this case study. To address this objective, LCLU was derived from Sentinel-2A/B Multispectral Instrument (MSI) data between 2017 and 2021 using time-series composites and a random forest (RF) classification model. Coordinates of infested locations, altitude, and locust development stages were collected during field observation campaigns between March and July 2022 and used in this study to assess actual and previous land cover situation of these locations. Findings show that 43% of detected locust locations were found on untilled, fallow, or uncultivated land and another 23% within a radius of 100 m to such areas. Furthermore, oviposition and breeding sites are mostly found in sparse vegetation (97%). This study demonstrates that up-to-date remote sensing data and target-oriented analyses can provide valuable information to contribute to early warning systems and decision support and thus to minimize the risk concerning this agricultural pest. This is of particular interest for all agricultural pests that are strictly related to changing human activities within transformed habitats.
... The global diversity comprises 28,650 valid species (Cigliano et al. 2020), of which 1166 species/subspecies belonging to 449 genera and 22 families are distributed in India (Gupta and Chandra 2019a, b). They are an essential component of grassland fauna in terrestrial ecosystems (Latchininsky et al. 2011). Recently an outbreak of desert locusts, Schistocerca gregaria (Forskal), was found severely damaging crops in Northern India (Joshi et al. 2020). ...
With more than one million named species, insects are the most diverse terrestrial creatures on the planet, representing around 75% of the global fauna. They contribute to invaluable ecosystem functions such as nutrient cycling, pollination, and seed dispersals and serve as a significant food source, aid in biocontrol of other organisms (such as predators, parasites), and maintain soil structure and fertility. Meantime, they are profoundly beneficial as pollinators. They often compete with humans, as pests of agriculture and stored products and as vectors of life-threatening diseases. Owning four of the globally recognised biodiversity hotspots—Himalaya, Indo Burma, Western Ghats and Sri Lanka, and Sundaland—India is represented by 67,111 insect species in four classes of subphylum Hexapoda: Collembola (345 species), Protura (20 species), Diplura (18 species), and Insecta (66,728 species), 64.8% of the overall faunal diversity of the country. Eight insect orders—Coleoptera, Lepidoptera, Hymenoptera, Diptera, Hemiptera, Orthoptera, Thysanoptera, and Odonata—form the majority (94%) of the insects in the country. This chapter further updates India’s known insect diversity, emphasising its diversity in ecosystems (such as aquatic, mangroves, soil, and forests) and biogeographic zones (Himalaya, Trans-Himalaya, Desert, and Islands). Additionally, information has been provided on the potential of insects in food security, pollination, forest pests, and their significance to medical and veterinary in context with Indian fauna. The chapter also includes a list of 27 insect species identified as invasive aliens in India and reports 22 species as threatened in the IUCN Red List from India. Keywords: Ecosystem diversity, Pollination, Food security, Threatened insects
... Short-horn grasshoppers (Orthoptera: Acrididae) are among the most diverse (> 6,700 described species) and ubiquitous fauna of grassland ecosystems around the world (Uvarov 1966, Latchininsky et al. 2011, Song et al. 2018 contributing, in some cases, to more than half of the total above-ground arthropod biomass (Gillon 1983, Song et al. 2018. The endemic short-horn grasshoppers of Aotearoa New Zealand occur widely, but are especially abundant in alpine habitats (Bigelow 1967, Trewick 2001, Trewick 2008, Trewick and Morris 2008, Koot et al. 2020. ...
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Body size is perhaps the most fundamental property of an organism and is central to ecology at multiple scales, yet obtaining accurate estimates of ecologically meaningful size metrics, such as body mass, is often impractical. Allometric scaling and mass-to-mass relationships have been used as alternative approaches to model the expected body mass of many species. However, models for predicting body size in key herbivorous insects, such as grasshoppers, exist only at the family level. To address this data gap, we collected empirical body size data (hind femur length and width, pronotum length, live fresh mass, ethanol-preserved mass, and dry mass) from 368 adult grasshoppers of three flightless species at Hamilton Peak, Southern Alps, New Zealand. We examined the relationships among body size components across all species using linear and non-linear regression models. Femur length and preserved mass were robust predictors of both fresh mass and dry mass across all species; however, regressions using preserved mass as a predictor always showed higher predictive power than those using femur length. Based on our results, we developed species-specific statistical linear mixed-effects models to estimate the fresh and dry masses of individual grasshoppers from their preserved mass and femur length. Including sex as an additional co-variate increased model fit in some cases but did not produce better estimates than traditional mass-to-mass and allometric scaling regressions. Overall, our results showed that two easy-to-measure, unambiguous, highly repeatable, and non-destructive size measures (i.e., preserved mass and femur length) can predict, to an informative level of accuracy, fresh and dry body mass across three flightless grasshopper species. Knowledge about the relationships between body dimensions and body mass estimates in these grasshoppers has several important ecological applications, which are discussed.
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The sensitivity of grasshoppers to disturbance makes them useful bioindicators for land management. The current study compared the grasshopper communities of three fallow-lands at different levels of human pressure: heavily used land (Ongot), moderately used land (Zamakoe), and least-used land (Ngutadjap). Grasshoppers were sampled by nets, pitfall traps, and box quadrats. Their species composition was analyzed using species-richness, abundance, abundance distribution-model, occurrence, and diversity indexes. Species number was not very different between localities. However, the opening up of forests by human activities offers suitable environment for the development or proliferation of the pest grasshopper populations such as Zonocerus variegatus (Linnaeus, 1758), Eyprepocnemis plorans (Charpentier, 1825), and Catantops sylvestrisJago, 1984, which are adapted to the very common Asteraceae found in fallow lands. Native forest species [such as Mazaea granulosa Stål, 1876, Holopercna gerstaeckeri (Bolívar, 1890), Digentia fasciataRamme, 1929] were, generally absent or rare and were collected in only forest/fallow-land ecotones. Low abundance and low occurrence of ecotone species fitted the log-normal abundance distribution model. The grasshopper communities of the less degraded localities were quite similar, but different from the Ongot community. Forest management by reforestation, reduction of slash-and-burn agriculture, and wood cutting, would restore the original grasshopper assemblages and general environmental health.
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Schistocerca gregaria (Forskl, 1775), one of the most notorious insects in the world, significantly harms the economy and agriculture each year. It was reputedly the biggest infestation to hit Pakistan since the 1990s, destroying wheat, rice, sugarcane, cotton, and vegetable crops, and it was also the cause of the worst disaster of 2019–2020. We have extensively examined the external characteristics of this swarm using the mitochondrial Cytochrome C Oxidase subunit 1 (COI), morphometry of the solitary and gregarious phases, influenced host plants, as well as its deterrent status. Swarms of Desert Locusts, which have been on the rise recently, have had a substantial negative influence on Pakistan's agriculture, destroying all kinds of crops. Preliminary projections of the financial losses over the two agricultural seasons in 2020 and 2021 may vary from 3.4 billion US dollars to 10.21 billion US dollars. This drastically increased the price of ordinary products in the market. In addition, locust activity has grown and is presently present in a number of affected areas. For the species to be managed and controlled effectively, accurate species identification is essential. This study seeks to explain this essential management attention
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Locusts are a threat to agriculture and livelihoods in many countries globally. The economic, social, and environmental consequences of these highly migratory pests are so substantial that they are treated as a national priority by many countries and several international commissions have been established to unite efforts. This book, a special issue of the Agronomy journal, aims to shed light on some overarching questions: What have we learned from historical outbreaks, how serious is the threat, what research is ongoing and is needed to better manage these insects, how should the world respond to plagues today especially in the context of climate change, are recommended preventive strategies really effective and what are the constraints to their application, and is there a possibility to make better use of biological alternatives to chemical pesticides? This book is freely accessible on the MDPI Books platform:
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Discrepancies in scale dynamics often make cohesive structural conclusions difficult, especially when dealing with ecological variance. We studied presence and abundance of grasshopper species in similar, yet distinct, montane habitat of southeast Wyoming and northern Colorado, USA. By limiting ecological variance, grasshopper species structure at two behavioral scales (grouped species dynamics and individual species interactions) was maximized with regard to soil texture and vegetative canopy coverage. Combining univariate and multivariate statistical methods, we note montane grasshopper species interactions to be scale dependent.
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In contrast to pests developing in close association with a particular host crop, locusts and grasshoppers are often controlled in natural or semi-natural landscapes, exposing structurally and functionally diverse communities to agrochemicals, chemicals to which they are not adapted. This suggests that insecticide-induced perturbations may be severe. On the other hand, with acridids being highly mobile, exposure of non-target biota at any one location tends to be rare, and insecticides might be seen as yet another component in a canon of stochastic and deterministic, natural or human-induced environmental catastrophes and selective forces, shaping communities and ecosystems. Moreover, habitat loss is by far the most important single threat to biodiversity, so why should doubt be cast on the potential and resilience of populations to recover from occasional insecticide stress? This paper reviews the environmental impact, as well as ecological and conceptual characteristics of acridid pest control. It concludes that ecologically significant risks may arise, in particular in ecosystems exposed to multiple stressors. Four priorities in ecological risk assessment and acridid pest management are proposed: 1) delimitation and characterization of sensitive areas within locust and grasshopper habitats, 2) ecosystem-specific, long-term field studies and operational monitoring, 3) real-time stewardship of control campaigns, with adequate participation of stakeholders, and 4) incorporation of the precautionary principle into decision-making and risk management.
Information on the potential loss of forage that might be expected from grasshopper feeding in a given season would benefit ranchers and land managers if the loss could be estimated in the spring before peak forage production. A method was developed for forecasting such losses on the northern mixed prairie when most species of grasshoppers are in the 3rd and 4th instars. The method is based on the assumptions that forage losses (forage consumed + destroyed) are directly proportional to grasshopper size and density and that during the period between the 3rd instar and death, which usually does not exceed 46 days, density decreases linearly to 0. Using feeding ratios (weight of forage destroyed/weight of adults), losses/day were calculated for each of 26 grasshopper species and for 3 groups of species separated by weight. Forecasted loss estimates for any population can be estimated if the density and species are determined, or a loss of 43 mg/grasshopper feeding day could be used as a general average if species cannot be identified. Forecasted losses are related to grasshopper density and to observed losses at one site in Montana during a 3-year period.
The objective of this study was to apply knowledge of holarctic grasshopper biogeography in representative, temperate ecosystems (Russia, South Siberia, Sayans region; 685,000 km^2 and USA, Wyoming; 272,000 km^2) to develop a comparative basis for understanding and conserving insect biodiversity. Maps of species distributions and vegetation zones were digitized, and a Geographic Information System was used to identify habitats with the greatest biodiversity and to characterize this diversity as a function of selected attributes. With respect to subfamilies, the greatest differences were in cold, mesic zones, where gomphocerines and melanoplines were dominant in Sayans and Wyoming, respectively. In terms of mobility, the Sayans has more flightless species and individuals, with the taiga supporting the greatest frequency of flightless acridids in both countries. With regard to feeding types, the diversity and richness of graminivores and forbivores were similar in the two regions, but mixed feeders were much more frequent in Wyoming. In the Sayans and Wyoming, pest species were most common in boreal and prairie zones, respectively. Ecoregions with a high diversity of pests also supported a high diversity of rare species. Shrub and desert zones supported many rare species in both countries. Thus, in terms of conservation, the Sayans' acridofauna appears to be at greater risk in terms of ecological vulnerability; acridid biodiversity is dispersed among habitats, with high frequencies of flightless and oligophagous species. The acridofauna of Wyoming could be conserved in fewer habitats than in the Sayans, but these habitats are subject to considerable human disturbance.
Experimental studies of the effects of grasshopper consumption on plant production are presented. The long held claim that grasshopper consumption of plants in some years can reduce forage for livestock and wildlife is supported. However, examining grasshopper consumption over a longer term (multiple years), I find that grasshoppers enhance plant production. This emerges because grasshoppers accelerate nutrient cycling primarily by increasing the proportion of litter provided by faster decomposing plants. The greater availability of nutrients further increases the abundance of faster decomposing plants because they are competitively favored under these conditions and this further enhances nutrient availability and plant production. Therefore, the short-term loss of forage for livestock and wildlife is outweighed by the long-term enhancement of forage production. The rangeland conditions which lead to grasshoppers producing beneficial production effects are reviewed.
This chapter updates former reviews on locust polyphenism and also discusses recent findings. Over 200 articles were published in scientific journals on various aspects of locust phase polyphenism, markedly advancing the knowledge of the subject. However, the chapter refers to the older literature when background information is necessary for complementary and better treatment, or because of historical importance. Some of the recent publications report contradictory findings, and such contradictions have been emphasized in the chapter. Substantial progress has been made in the study of locust phase polyphenism over the past several years. The topic has well and truly emerged from the realms of applied entomology to assume a prominent position in the modern study of phenotypic plasticity, whereby adaptive phenotypes arise during development as a result of plastic interactions between genes and the environment. The study of behavioral gregarization has seen some of the most far-reaching progress. The involvement of locust-emitted volatiles in aspects of phase biology has generated substantial research and its fair share of productive controversy. It has been especially heartening to see that some of the major areas of controversy, such as the role of phenylacetonitrile, appear to have been at least partially resolved during the past year. New genetic resources also offer a solution to a more prosaic problem in locust research. There has been a growing realization that some of the differences reported between laboratories in aspects of phase polyphenism most likely reflect effects of rearing locusts in long-term culture in the laboratory.
Studies showed that the type of damage, the timing of damage with the phenological stage of the crop, and the amount of available soil moisture influenced the growth response of spring wheat to acute levels of grasshopper damage and acute levels of artificial damage. Ground-level cutting of plants resulted in the greatest reduction in plant biomass and crop yield, while grasshopper damage and artificial stripping of leaf material did not result in as severe a reduction in either biomass or yield. Damaged plants were not able to recover lost biomass when damage occurred any later than the early stages of tillering despite observed relative growth rates which were higher than control plants. The greatest degree of recovery occurred in study sites with the greatest amount of available soil moisture. The most detrimental effect of damage on yield was the reduction of heads per plant and kernel weight. In most cases differences in the number of seeds per head between damaged and control plants were not evident.
Opinions expressed in this article are entirely those of the author. Acridid pests, locusts and grasshoppers, pose continuing threats to rural communities in developing countries, including sub-Saharan Africa, where human and material resources for controlling these insects are meager to none. The past 15 y have witnessed invasions, upsurges and/or plague of the desert locust, Schistocerca gregaria, mixed at times with the migratory locust, Locusta migratoria migratorioides, and the Senegalese grasshopper, Oedaleus senegalensis—in outbreak and invasion areas in the Sahel, northwestern Africa, the Red Sea region, and southwest Asia. Strained by lack of resources to develop and implement integrated pest management strategies that embrace effective preventive control alternatives, affected countries often resort to spraying enormous quantities of synthetic chemical pesticides to control these pests. During the 2003–05 and 1993–94 upsurges, and the 1986–89 locust/grasshopper plague, close to 25 million liters of pesticides were sprayed, largely with the help of the international community. At current estimates, that may have meant upwards of US$500 million in control cost alone, not to mention associated environment and nontarget costs. This paper attempts an overview of the challenges, impacts, and implications of the current approach, its perceived and actual benefits to rural communities and the dilemma in donors' actions or inactions. It also tries to capture lessons learned and experiences gained from recent and past campaigns and to draw conclusions and offer recommendations for future directions.
Magor, J.I., Lecoq, M., Hunter, D.M. [2008. Preventive control and desert locust plagues. Crop Protection 27, 1527–1533, doi:10.1016/j.cropro.2008.08.006], claim that their version of a desert locust preventive control programme has caused plagues to be rarer, shorter and geographically more limited, but without producing any evidence of control campaign success. There are many reasons why success is unlikely, some of which they admit. Their “model” does not support the case; it has sundry flaws and is not consistent with actual events.