The Evolution of Complex Life Cycle Phenomena: An Ecological Perspective

Istock, Conrad A.

doi:10.1111/j.1558-5646.1967.tb03414.x

Cited by 134 publications

(81 citation statements)

References 9 publications

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“…Thus the life cycle contains an option of one or two discrete energy resources; it is complex in a developmental (holometabolic) sense, but it is marginally, occasionally, or not all complex in an ecological sense. It represents an extreme case of the evolutionary reduction of a complex life cycle (Istock, 1967). This elimination of the adult as a required energy-gathering stage is accompanied by striking ovarian precocity, with egg maturation relegated to the pupa to an unusual degree (Smith and Brust, 1971).…”

Section: Study Sitementioning

confidence: 99%

“…Widespread autogeny in mosquitoes may be a manifestation of evolutionary instability in such complex life cycles (Istock, 1967). Obligate autogeny as a solution to the intricate evolutionary problems which arise for species with a complex life cycle probably requires that a species or sub-unit of a species (such as the reproductively isolated autogenous C. pipiens populations of Spielman, 1964) retain a fertility of 25 to 80 eggs per female completing the life cycle.…”

Section: The Evolution Of Autogenymentioning

confidence: 99%

“…The ecological and evolutionary consequences of a complex life cycle (two or more distinct ecological stages) are of some interest (Istock, 1967(Istock, , 1970. The species…”

mentioning

confidence: 99%

“…The ecological and evolutionary consequences of a complex life cycle (two or more distinct ecological stages) are of some interest (Istock, 1967(Istock, , 1970. The species is an obligate colonizer, following over the seasons and the years the production of new water-filled leaves by the pitcher-plant, Sarracenia purpurea; hence, we can test some of the existing theory for the evolution of colonizing species (Lewontin, 1965).…”

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confidence: 99%

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Ecology and Evolution of the Pitcher‐plant Mosquito: 1. Population Dynamics and Laboratory Responses to Food and Population Density

1975

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It is commonplace to emphasize that ecological and evolutionary processes are related and ought to be studied together, but analyses of natural populations which unravel the interrelations of historical evolutionary factors, current population processes, and the prevailing effects of natural selection are not common. This is the direction of our studies of the pitcher-plant mosquito, Wyeomyia smithii. In this paper we present: the natural history and population dynamics of this species in a single bog; an experiment to determine if the larval part of the population saturates its resources at a critical time preceding metamorphosis; and studies of laboratory responses of the species to food and population density.The field data show that larval abundance is more tightly regulated (i.e., steadier) than the abundance of other parts of the life cycle. Our laboratory data show how the components of fitness are influenced by different food levels and larval density. Central in these studies is completion of the life cycle. We are trying to understand the factors which encourage or discourage completion of the life cycle and influence the average fitness of individuals under different ecological circumstances.Study of W. smithii was undertaken for a variety of conceptual and practical reasons. The ecological and evolutionary consequences of a complex life cycle (two or more distinct ecological stages) are of some interest (Istock, 1967(Istock, , 1970. The species

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Section: Study Sitementioning

confidence: 99%

Section: The Evolution Of Autogenymentioning

confidence: 99%

“…The ecological and evolutionary consequences of a complex life cycle (two or more distinct ecological stages) are of some interest (Istock, 1967(Istock, , 1970. The species…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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Ecology and Evolution of the Pitcher‐plant Mosquito: 1. Population Dynamics and Laboratory Responses to Food and Population Density

1975

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“…Such dual or multiniche cycles ("complex life cycles" of Istock [1967]; Wilbur, 1980) may arise from a complex developmental pathway involving metamorphosis of a single individual, as in holometabolous insects, amphibians, and many marine invertebrates. Alternatively, they may stem from phenotypic divergence of different generations in a multiple-generation cycle.…”

mentioning

confidence: 99%

EVOLUTIONARY REDUCTION OF COMPLEX LIFE CYCLES: LOSS OF HOST‐ALTERNATION IN PEMPHIGUS (HOMOPTERA: APHIDIDAE)

Moran

Whitham

1988

Evolution

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Abstract. -In a Utah canyon, the aphid, Pemphigus betae, exhibits two life cycles: a cycle involving host-alternation between cottonwood trees and roots of herbaceous plants and a secondarily reduced cycle, in which the cottonwood generations are eliminated so that wingless forms live year round on roots. Relative frequencies of the two life-cycle types vary along a 30-km stretch of the canyon, with the reduced cycle predominating at upper sites. Factors underlying this life-cycle variation were examined with common-garden and transfer experiments. Results showed 1) a facultative increase in production of alternating forms in response to crowding in root colonies, 2) a genetic component to both within-and between-site variation in tendency to produce alternating morphs, and 3) site-specific environmental effects on level of investment in the reduced versus alternating life cycles. Thus, the variation in frequency of life-cycle reduction in this aphid is dependent on a complex of interdependent factors. These include adaptive phenotypic plasticity, microgeographically variable cues affecting mechanisms ofmorph determination, and genetically based variation in tendency to show reduction versus alternation.Genetic variation between sites corresponds to microgeographic variation in success oflife-cycle phases. Where cottonwood hosts are absent (lower elevations) or where the cottonwood phase has low survival (upper elevations), clones tend to produce fewer migrating morphs, as compared to clones from middle elevations, where the cottonwood phase is relatively favorable. Such independence between conditions in alternate phases is a general feature of complex life cycles and can generate strong site-specific selection for permanent life-cycle reduction. Such life-cycle shifts have sometimes been followed by extensive radiations in aphids and other groups.

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Experimental analysis of character coupling across a complex life cycle: Pigment pattern metamorphosis in the tiger salamander,Ambystoma tigrinum tigrinum

Parichy¹

1998

J. Morphol.

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Developmental relationships among characters are expected to bias patterns of morphological variation at the population level. Studies of character development thus can provide insights into processes of adaptation and the evolutionary diversification of morphologies. Here I use experimental manipulations to test whether larval and adult pigment patterns are coupled across metamorphosis in the tiger salamander, Ambystoma tigrinum tigrinum (Ambystomatidae). Previous investigations showed that the early larval pigment pattern depends on interactions between pigment cells and the lateral line sensory system. In contrast, the results of this study demonstrate that the major features of the adult pigment pattern develop largely independently of both the early larval pattern and the lateral lines. These results suggest that ontogenetic changes that occur across metamorphosis decouple larval and adult pigment patterns and could thereby facilitate independent evolutionary modifications to the patterns during different stages of the life cycle. J. Morphol. 237:53–67, 1998. © 1998 Wiley‐Liss, Inc.

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The Evolution of Complex Life Cycle Phenomena: An Ecological Perspective

Cited by 134 publications

References 9 publications

Ecology and Evolution of the Pitcher‐plant Mosquito: 1. Population Dynamics and Laboratory Responses to Food and Population Density

Ecology and Evolution of the Pitcher‐plant Mosquito: 1. Population Dynamics and Laboratory Responses to Food and Population Density

EVOLUTIONARY REDUCTION OF COMPLEX LIFE CYCLES: LOSS OF HOST‐ALTERNATION IN PEMPHIGUS (HOMOPTERA: APHIDIDAE)

Experimental analysis of character coupling across a complex life cycle: Pigment pattern metamorphosis in the tiger salamander,Ambystoma tigrinum tigrinum

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