Outbreaks and recession populations of the desert locust <i>Schistocerca gregaria</i> (Forsk.)

Roffey, J.; Popov, G. B.; Hemming, C. F.

doi:10.1017/s0007485300003679

Cited by 27 publications

(24 citation statements)

References 10 publications

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“…This latter observation suggests that population increases in complementary breeding areas are involved. Analysts (Waloff, 1966; Roffey et al., 1970; Bennett, 1976) all emphasize the distinction between ‘local outbreaks’ and the more numerous and widespread ‘contemporaneous ones’ that initiate upsurges. This ambiguity in contemporary terminology exemplifies Waloff's (1966) warning to regard desert locust definitions as provisional in the absence of quantitative values for recession and plague fluctuations.…”

Section: Defining Outbreaks Upsurges and Plaguesmentioning

confidence: 99%

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Preventing desert locust plagues: optimizing management interventions

Huis

Cressman²,

Magor

2007

Entomologia Exp Applicata

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Solitarious desert locusts, Schistocerca gregaria (Forskål) (Orthoptera: Acrididae), inhabit the central, arid, and semi-arid parts of the species' invasion area in Africa, the Middle East, and South-West Asia. Their annual migration circuit takes them downwind to breed sequentially where winter, spring, and summer rains fall. In many years, sparse and erratic seasonal rains support phase change and local outbreaks at only a few sites. Less frequently, seasonal rains are widespread, frequent, heavy, and long lasting, and many contemporaneous outbreaks occur. When such seasonal rains fall sequentially, populations develop into an upsurge and eventually into a plague unless checked by drought, migration to hostile habitats, or effective control. Increases in the proportion of gregarious populations as the plague develops alter the effectiveness of control. As an upsurge starts, only a minority of locusts is aggregated into treatable targets and spraying them leaves sufficient unsprayed individuals to continue the upsurge. Spraying all individuals scattered within an entire infested zone is arguably both financially and environmentally unacceptable. More of the population gregarizes and forms sprayable targets after each successive season of good rains and successful breeding. Eventually, unless the rains fail, the entire upsurge population becomes aggregated at high densities so that the infested area diminishes and a plague begins. These populations must continue to increase numerically and spread geographically to achieve peak plague levels, a stage last reached in the 1950s. Effective control, aided by poor rains, accompanied each subsequent late upsurge and early plague stage and all declined rapidly. The control strategy aims to reduce populations to prevent plagues and damage to crops and grazing. Differing opinions on the optimum stage to interrupt pre-plague breeding sequences are reviewed.

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Section: Defining Outbreaks Upsurges and Plaguesmentioning

confidence: 99%

“…Roffey et al. (1970) summarising observations on the recession populations during the 1960s concluded that outbreaks, upsurges, and plagues belonged to a single continuum.…”

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confidence: 99%

Preventing desert locust plagues: optimizing management interventions

Huis

Cressman²,

Magor

2007

Entomologia Exp Applicata

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“…In fact, dynamically unstable global populations are characteristic of a variety of social systems. Most notable among these are the tree-killing bark beetles (Berryman 1973;Raffa and Berryman 1987) and the migratory locusts (Roffey et al 1968;Uvarov 1977) among nonkin-based systems and the tent caterpillars (Myers 1993), prairie voles (Getz et al 1987;Getz and McGuire 1997), and red grouse (Matthiopoulos et al 2000) among kin-based systems. The tree-killing bark beetles, in particular, closely match the assumptions of our model (Berryman 1973;Raffa and Berryman 1987).…”

Section: Associations Among Nonrelatives and The Intrinsic Rate Of Grmentioning

confidence: 99%

Population Ecology, Nonlinear Dynamics, and Social Evolution. I. Associations among Nonrelatives

Avilés

Abbot

Cutter

2002

The American Naturalist

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Using an individual-based and genetically explicit simulation model, we explore the evolution of sociality within a population-ecology and nonlinear-dynamics framework. Assuming that individual fitness is a unimodal function of group size and that cooperation may carry a relative fitness cost, we consider the evolution of one-generation breeding associations among nonrelatives. We explore how parameters such as the intrinsic rate of growth and group and global carrying capacities may influence social evolution and how social evolution may, in turn, influence and be influenced by emerging group-level and population-wide dynamics. We find that group living and cooperation evolve under a wide range of parameter values, even when cooperation is costly and the interactions can be defined as altruistic. Greater levels of cooperation, however, did evolve when cooperation carried a low or no relative fitness cost. Larger group carrying capacities allowed the evolution of larger groups but also resulted in lower cooperative tendencies. When the intrinsic rate of growth was not too small and control of the global population size was density dependent, the evolution of large cooperative tendencies resulted in dynamically unstable groups and populations. These results are consistent with the existence and typical group sizes of organisms ranging from the pleometrotic ants to the colonial birds and the global population outbreaks and crashes characteristic of organisms such as the migratory locusts and the tree-killing bark beetles.

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“…The understanding of the biological factors involved in outbreaks and swarm formation in locusts requires studies on different spatial scales, from micro to macro 4,8,11,12,33 . The current study was performed on a macro scale, ranging from individual plants to a limited area of natural habitat and revealed a detailed examination of the relationship between solitarious locusts and plant quality.…”

Section: Discussionmentioning

confidence: 99%