DOCSLIB.ORG

Conserving Species-Rich Predator Assemblages Strengthens Natural Pest Control in a Climate Warming Context

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Conserving Species-Rich Predator Assemblages Strengthens Natural Pest Control in a Climate Warming Context Agricultural and Forest Entomology (2016), DOI: 10.1111/afe.12180 Conserving species-rich predator assemblages strengthens natural pest control in a climate warming context ∗†‡ ∗† Robin Drieu and Adrien Rusch ∗INRA, ISVV, UMR 1065 Santé et Agroécologie du Vignoble, F-33883, 71 rue Edouard Bourlaux, Villenave d’Ornon, France, †INRA UMR 1065 Santé et Agroécologie du Vignoble, Bordeaux Sciences Agro, Université de Bordeaux, F-33883, 71 rue Edouard Bourlaux, Villenave d’Ornon, France and ‡Centre International D’études Supérieures en Sciences Agronomiques, Montpellier SupAgro, Place Pierre Viala, 34060, Montpellier, France Abstract 1 Recent evidence has shown that a consideration of multiple drivers is important if we want to understand how ecosystem functioning will respond to global change. 2 In the present study, we used a substitutive approach to examine how two major components of global change, warming and predator diversity, affect the top-down control of two phytophagous insect pests. Predator assemblages were created using a substitutive design to give three single-species treatments (low diversity) and one three-species treatment (high diversity) under two temperature treatments (current seasonal temperature and an increase of +3∘C over current temperatures). 3 The results obtained indicate a shift from substitutive to complementarity effects among predatory species with experimental warming. Experimental warming revealed complementarity between the predatory species in diverse assemblages because higher predation rates on both prey species were found in the high diversity treatment compared with what was expected based on low diversity treatments at the same temperature. 4 Our analyses of prey selectivity provided evidence that resource-niche partitioning is involved in the emergence of functional complementarity under warming. The present study highlights the importance of maintaining diverse predator assemblages if we want to increase natural pest control services in agroecosystems and reduce dependence on agrochemicals in a climate change context. Keywords Agroecosystems, biodiversity, biodiversity-ecosystem functioning, climate change, food web, grapevine, multiple predator, trophic cascade. Introduction Changes in abiotic conditions such as temperature affect the strength of trophic interactions that play critical roles in the func- The effects of global environmental changes are predicted to tioning of terrestrial ecosystems (Schmitz, 2003; Barton et al., become more important in the future, such as increases in tem- 2009; Barton & Ives, 2014). Temperature affects seasonal phe- perature and atmospheric CO , as well as losses of biodiver- 2 nology, metabolic rate or the behaviour of arthropod predators, sity or biological invasions that are triggered and maintained by with potential important consequences related to the top-down human activities (Tylianakis et al., 2008). Several studies have control of herbivores and primary producers (Schmitz & Bar- revealed that global environmental changes can affect the geo- ton, 2014). Moreover, empirical studies have reported that direct graphical distribution and community composition of plant and effects of predators on herbivores may be reduced at elevated animal communities (Tylianakis et al., 2008; Sarmento et al., 2010; Walther, 2010; Harley, 2011). These modifications are pre- temperatures (Barton, 2010; Laws & Joern, 2013) and also dicted to alter direct and indirect interactions among species that cascading effects related to invertebrate predators on plant and therefore ecosystem functioning (Tylianakis et al., 2008). communities can be magnified at elevated temperatures (Bar- However, the empirical evidence related to such effects remains ton & Schmitz, 2009; Barton et al., 2009). Furthermore, labo- limited (Dossena et al., 2012; Barton & Ives, 2014). ratory and modelling studies have found higher feeding rates and short-term per capita interaction strength between predators Correspondence: Adrien Rusch. Tel.: +33 557122643; e-mail: and their prey at higher temperature, suggesting a higher level [email protected] of top-down control at higher temperatures (Rall et al., 2010; © 2016 The Royal Entomological Society 2 R. Drieu and A. Rusch Vucic-Pestic et al., 2011). This variability of outcomes suggests a of predatory species will occur in the ambient temperature high context-dependency of trophic interaction responses to ele- treatment because the complementary habitat domain limited vated temperature, where some interactions are magnified under interspecific interactions between predators. We expected that warming, whereas others are weakened. Moreover, because the warming effect on predators and prey will affect the feeding species differ greatly in their thermal tolerance and because niche of predators and modify the emergent effects of multiple increased temperatures affect foraging, consumption and diges- assemblages on predation rates from the substitutable effect to tion, as well as growth rates of both predators and prey, warming either risk reducing or risk enhancement for the prey. We also is assumed to potentially alter the relative strengths of top-down expected higher predation rates by individual predatory species and bottom-up effects in an ecosystem (Hoekman, 2010). in the elevated temperature treatment compared with ambient Both diversity and community composition of predators can temperature as a result of accelerated metabolism. influence the magnitude of top-down control in different ways. First, a large body of work related to biodiversity and ecosys- tem functioning suggests that a higher predator diversity leads to an increase in overall predation rates caused by niche par- Materials and methods titioning, facilitation or a higher probability of having efficient Study system predators included in the community as the number of species increases (Letourneau et al., 2009; Cardinale et al., 2012). Sec- We selected grapevine (Vitis vinifera) to test our hypothe- ond, empirical evidence indicates that increasing predator diver- ses for several reasons. First, various pests attack vineyards sity may lead to various effects on the extent of top-down con- resulting in very intensive pesticide treatments; approximately trol. Studies have found reduced top-down control as a result of 20% of the phytochemicals sprayed in agriculture in France, negative interactions among predators such as intraguild preda- measured in tons, are used to treat vineyards (Aubertot et al., tion (Martin et al., 2013). Other studies have reported a similar 2006). Moreover, this perennial crop hosts a large number of level of top-down control at a different level of predator diversity different pest species and grows in areas that are expected caused by the balance between positive and negative interactions to experience climate change in the near future with impor- (Straub et al., 2008; Letourneau et al., 2009). Finally, recent stud- tant consequences for crop production and biodiversity (Han- ies have demonstrated that important functional traits, such as nah et al., 2013). Reducing agrochemical use at the same hunting-mode, relative body size or habitat domain of predator time as maintaining yield and preserving biodiversity in those and prey, are good predictors of the rate of top-down control of agroecosystems will therefore be a major applied challenge in herbivores by their natural enemies (Schmitz, 2008; Schneider the near future. et al., 2012; Rusch et al., 2015). Our experiment used two common leafhopper (Hemiptera: Biodiversity loss is a major component of global change Cicadellidae) species that infest vines: the green leafhopper (Hooper et al., 2012). Declines in biodiversity over time have Empoasca vitis (Gothe) and the Flavescence dorée leafhopper been observed for many different communities, including nat- Scaphoideus titanus (Ball). These two leafhoppers can cause ural enemies of crop pests because of changes in climate, land severe damage to grapevine. Empoasca vitis feeds by punctur- use or farming practices (Robinson & Sutherland, 2002; Thomas ing phloem vessels of the leaves leading to obstruction of the et al., 2004). However, the way that predator diversity will affect vessels and leaf necrosis, thereby resulting in a reduced pho- top-down control in agroecosystems remains poorly understood tosynthetic rate and delayed fruit maturity (Chuche & Thiéry, (Letourneau et al., 2009). There is increasing concern that stud- 2014). Scaphoideus titanus is the only known vector of Flaves- ies investigating the consequences of individual components of cence dorée, a phytoplasma-borne disease, one of the most global change may not reflect their synergistic or antagonistic severe and damaging diseases in European vineyards; this dis- joint effects in real ecosystems or ecological communities (Did- ease causes major economic losses (Chuche & Thiéry, 2014). ham et al., 2007; Tylianakis et al., 2008; Hoover et al., 2012; These two leafhopper species are found at the same time Rosenblatt & Schmitz, 2014). Complex interactions between period on vines but usually occur at different phenological multiple drivers of global change provide an important reason stages (adult and larva). Both species are mainly active at night for considering more than one driver if we are to understand how (from 18.00 to 08.00 h) and stay on the leaves during the day ecosystem functioning will respond to global change. (Lessio & Alma, 2004). In the present study, we examined how
Load more

Recommended publications
  • The Genetic Mechanism of Selfishness and Altruism in Parent-Offspring Coadaptation Min Wu, Jean-Claude Walser, Lei Sun and Mathias Kölliker
    SCIENCE ADVANCES | RESEARCH ARTICLE EVOLUTIONARY BIOLOGY Copyright © 2020 The Authors, some rights reserved; The genetic mechanism of selfishness and altruism exclusive licensee American Association in parent-offspring coadaptation for the Advancement Min Wu1*, Jean-Claude Walser2, Lei Sun3†, Mathias Kölliker1*‡ of Science. No claim to original U.S. Government Works. Distributed The social bond between parents and offspring is characterized by coadaptation and balance between altruistic under a Creative and selfish tendencies. However, its underlying genetic mechanism remains poorly understood. Using transcriptomic Commons Attribution screens in the subsocial European earwig, Forficula auricularia, we found the expression of more than 1600 genes License 4.0 (CC BY). associated with experimentally manipulated parenting. We identified two genes, Th and PebIII, each showing evidence of differential coexpression between treatments in mothers and their offspring. In vivo RNAi experiments confirmed direct and indirect genetic effects of Th and PebIII on behavior and fitness, including maternal food provisioning and reproduction, and offspring development and survival. The direction of the effects consistently indicated a reciprocally altruistic function for Th and a reciprocally selfish function for PebIII. Further metabolic pathway analyses suggested roles for Th-restricted endogenous dopaminergic reward, PebIII-mediated chemical communication and a link to insulin signaling, juvenile hormone, and vitellogenin in parent-offspring Downloaded from coadaptation and social evolution. INTRODUCTION manipulations with and without mother-offspring contact, without Parents and offspring influence each other’s behavior and evolutionary detrimental effects on offspring. Females produce one or two clutches http://advances.sciencemag.org/ fitness through reciprocal interactions (1). As an altruistic trait, over their lifetime and provide food (see movie S1) and protection parental care is beneficial to the survival and development of offspring to their young nymphs (8, 9).
    [Show full text]
  • Harvest-Spiders 515
    PROVISIONAL ATLAS OF THE REF HARVEST-SPIDERS 515. 41.3 (ARACHNIDA:OPILIONES) OF THE BRITISH ISLES J H P SANKEY art å • r yz( I is -..a .e_I • UI II I AL _ A L _ • cta • • .. az . • 4fe a stir- • BIOLOGICAL RECORDS CENTRE Natural Environment Research Council Printed in Great Britain by Henry Ling Ltd at the Dorset Press, Dorchester, Dorset ONERC Copyright 1988 Published in 1988 by Institute of Terrestrial Ecålogy Merlewood Research Station GRANGE-OVER-SANDS Cumbria LA1/ 6JU ISBN 1 870393 10 4 The institute of Terrestrial Ecology (ITE) was established in 1973, from the former Nature Conservancy's research stations and staff, joined later by the Institute of Tree Biology and the Culture Centre of Algae and Protozoa. ITO contribbtes to, and draws upon, the collective knowledge of the 14 sister institutes which make up the Natural Environment Research Council, spanning all the environmental sciences. The Institute studies the factors determining the structure, composition and processes of land and freshwater systems, and of individual plant and animal species. It is developing a sounder scientific basis for predicting and modelling environmental trends arising from natural or man-made change. The results of this research are available to those responsible for the protection, management and wise use of our natural resources. One quarter of ITE's work is research commissioned by customers, such as the Department of Environment, the European Economic Community, the Nature Conservancy Council and the Overseas Development Administration. The remainder is fundamental research supported by NERC. ITE's expertise is widely used by international organizations In overseas projects and programmes of research.
    [Show full text]
  • De Hooiwagens 1St Revision14
    Table of Contents INTRODUCTION ............................................................................................................................................................ 2 CHARACTERISTICS OF HARVESTMEN ............................................................................................................................ 2 GROUPS SIMILAR TO HARVESTMEN ............................................................................................................................. 3 PREVIOUS PUBLICATIONS ............................................................................................................................................. 3 BIOLOGY ......................................................................................................................................................................... 3 LIFE CYCLE ..................................................................................................................................................................... 3 MATING AND EGG-LAYING ........................................................................................................................................... 4 FOOD ............................................................................................................................................................................. 4 DEFENCE ........................................................................................................................................................................ 4 PHORESY,
    [Show full text]
  • Behavioral Roles of the Sexually Dimorphic Structures in the Male Harvestman, Phalangium Opilio (Opiliones, Phalangiidae)
    1763 Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae) Rodrigo H. Willemart, Jean-Pierre Farine, Alfredo V. Peretti, and Pedro Gnaspini Abstract: In various animal species, male sexual dimorphic characters may be used during intrasexual contests as orna- ments to attract females, or to hold them before, during, or after copulation. In the well-known harvestman, Phalangium opilio L., 1758, the behavioral functions of these male sexually dimorphic structures have never been studied in detail. Therefore, in addition to a morphometric study, 21 male contests and 43 sexual interactions were analyzed. Our observa- tions revealed that during contests, the male cheliceral horns form a surface by which the contestants use to push each other face-to-face while rapidly tapping their long pedipalps against the pedipalps of the opponent, occasionally twisting the opponent’s pedipalp. Scanning electron micrographs revealed contact mechanoreceptors on the pedipalp that would de- tect the intensity–frequency of contact with the contender’s pedipalp. Larger males won almost all contests, whereas the loser rapidly fled. During sexual interactions, the longer pedipalps of the male held legs IV of the female, whereas males with shorter pedipalps held the female by legs III. No contact with the male pedipalps and chelicerae by the females was visible before, during, or after copulation. Soon after copulating, males typically bent over the female, positioning their cheliceral horns against the females’s dorsum. Consequently, our data show that the cheliceral horns and the longer pedi- palps of the male seem to play an important role, during both intersexual and intrasexual encountering.
    [Show full text]
  • European Earwig, Forficula Auricularia Linnaeus (Insecta: Dermaptera: Forficulidae)1
    Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office. EENY-032 European Earwig, Forficula auricularia Linnaeus (Insecta: Dermaptera: Forficulidae)1 H. V. Weems, Jr., and P. E. Skelley2 Introduction Distribution The European earwig, Forficula auricularia This earwig is found throughout Europe, but it Linnaeus 1758, is intercepted in Florida frequently in seldom is present in great numbers. Quantities of bundles of plants and shrubbery, in cut flowers, and nursery stock arrive from the western United States in florists' equipment arriving from the western annually that are infested with this earwig, but it has United States. This insect is spread largely by man. not successfully established in Florida. While it has Spread by natural means is limited because earwigs not been considered of great economic importance in seldom fly and cannot maintain flight very long. It Europe, it has become a serious pest in parts of the has not yet become established in Florida, but it has United States. the potential to do so, at least in the northern part of the state. This earwig was recorded first in the United The European earwig is widespread in cooler States at Newport, Rhode Island in 1911 (Jones parts of the world. Originally known from the 1917). Jones (1917) reported a small colony from Palearctic Region, the European earwig has been Seattle, Washington in 1915. Later evidence indicated recorded from Canada (British Columbia, Manitoba, that it first invaded North America somewhere on the Newfoundland, Nova Scotia, Ontario, Quebec, and west coast in the early 1900s. Eventually it became Saskatchewan) and the United States (Arizona, widespread in the New England and Middle Atlantic California, Colorado, Idaho, Maine, Massachusetts, states and throughout most of the western states, Montana, New York, North Carolina, Oregon, Rhode especially where there is abundant rainfall or Island, Utah, and Washington).
    [Show full text]
  • Laboratory Rearing of Phalangium Opilio (Arachnida: Opiliones)
    The Great Lakes Entomologist Volume 1 Number 8 -- June 1968 Number 8 -- June 1968 Article 3 June 1968 Laboratory Rearing of Phalangium Opilio (Arachnida: Opiliones) George E. Klee Michigan State University James W. Butcher Michigan State University Follow this and additional works at: https://scholar.valpo.edu/tgle Part of the Entomology Commons Recommended Citation Klee, George E. and Butcher, James W. 1968. "Laboratory Rearing of Phalangium Opilio (Arachnida: Opiliones)," The Great Lakes Entomologist, vol 1 (8) Available at: https://scholar.valpo.edu/tgle/vol1/iss8/3 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at [email protected]. Klee and Butcher: Laboratory Rearing of Phalangium Opilio (Arachnida: Opiliones) 1968 THE MICHIGAN ENTOMOLOGIST 275 LABORATORY REARING OF PHALANGIUM OPILIO ( ARACHNIDA: OPILIONES) ' George E. Klee and James W. Butcher Department of Entomology, Michigan State University East Lansing, Michigan 48823 While a good deal of work has been reported on the natural history and ecology of the opiliones in Europe and England (Bristowe, 1949; Sankey, 1949; Todd, 1949; Phillipson, 1959; Savory, 1964; Juberthie, 1965), this important group has received little attention in North America. Bishop (1949) published a concise synopsis of reactions and general habits of the opiliones of New York and, in a Ph. D. dissertation, Edgar (1960) described the biology of the order in Michigan. Current studies at Michigan State University on the effects of insecticides on non-target organisms have revealed an acute lack of biological information on the group, and before the effects of insecticides could be determined, life histories of the opiliones had to be clarified.
    [Show full text]
  • Invertebrates of Slapton Ley National Nature Reserve (Fsc) and Prawle Point (National Trust)
    CLARK & BECCALONI (2018). FIELD STUDIES (http://fsj.field-studies-council.org/) INVERTEBRATES OF SLAPTON LEY NATIONAL NATURE RESERVE (FSC) AND PRAWLE POINT (NATIONAL TRUST) RACHEL J. CLARK AND JANET BECCALONI Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD. In 2014 the Natural History Museum, London organised a field trip to Slapton. These field notes report on the trip, giving details of methodology, the species collected and those of notable status. INTRODUCTION OBjectives A field trip to Slapton was organised, funded and undertaken by the Natural History Museum, London (NHM) in July 2014. The main objective was to acquire tissues of UK invertebrates for the Molecular Collections Facility (MCF) at the NHM. The other objectives were to: 1. Acquire specimens of hitherto under-represented species in the NHM collection; 2. Provide UK invertebrate records for the Field Studies Council (FSC), local wildlife trusts, Natural England, the National Trust and the National Biodiversity Network (NBN) Gateway; 3. Develop a partnership between these organisations and the NHM; 4. Publish records of new/under-recorded species for the area in Field Studies (the publication of the FSC). Background to the NHM collections The NHM is home to over 80 million specimens and objects. The Museum uses best practice in curating and preserving specimens for perpetuity. In 2012 the Molecular Collections Facilities (MCF) was opened at the NHM. The MCF houses a variety of material including botanical, entomological and zoological tissues in state-of-the-art freezers ranging in temperature from -20ºC and -80ºC to -150ºC (Figs. 1). As well as tissues, a genomic DNA collection is also being developed.
    [Show full text]
  • THE EARWIGS of CALIFORNIA (Order Dermaptera)
    BULLETIN OF THE CALIFORNIA INSECT SURVEY VOLUME 20 THE EARWIGS OF CALIFORNIA (Order Dermaptera) BY ROBERT L. LANGSTON and J. A. POWELL UNIVERSITY OF CALIFORNIA PRESS THE EARWIGS OF CALIFORNIA (Order Dermaptera) BULLETIN OF THE CALIFORNIA INSECT SURVEY VOLUME 20 THE EARWIGS OF CALIFORNIA (Order Dermaptera) BY ROBERT L. LANGSTON and J. A. POWELL UNIVERSITY OF CALIFORNIA PRESS BERKELEY LOS ANGELES LONDON 1975 BULLETIN OF THE CALIFORNIA INSECT SURVEY Advisory Editors: H. V. Daly, J. A. Powell; J. N. Belkin, R. M. Bohart, R. L. Doutt, D. P. Furman, J. D. Pinto, E. I. Schlinger, R. W. Thorp VOLUME 20 Approved for publication September 20,1974 Issued August 15, 1975 UNIVERSITY OF CALIFORNIA PRESS BERKELEY AND LOS ANGELES UNIVERSITY OF CALIFORNIA PRESS, LTD. LONDON, ENGLAND ISBN 0-520-09524-3 LIBRARY OF CONGRESS CATALOG CARD NUMBER: 74-22940 0 1975 BY THE REGENTS OF THE UNIVERSITY OF CALIFORNIA PRINTED BY OFFSET IN THE UNITED STATES OF AMERICA CONTENTS Introduction .................................................. 1 California fauna ............................................. 1 Biology ................................................... 1 History of establishment and spread of introduced species in California ........ 2 Analysis of data ............................................. 4 Acknowledgments ............................................ 4 Systematic Treatment Classification ............................................... 6 Key to California species ........................................ 6 Anisolabis maritima (Ght5) ...................................
    [Show full text]
  • Enhancing Biological Control in Apple Orchards Jaume Lordan Sanahuja
    Enhancing biological control in apple orchards Jaume Lordan Sanahuja Dipòsit Legal: L.1233-2014 http ://hdl.handle.net/10803/275941 ADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs. ADVERTENCIA. El acceso a los contenidos de esta tesis doctoral y su utilización debe respetar los derechos de la persona autora. Puede ser utilizada para consulta o estudio personal, así como en actividades o materiales de investigación y docencia en los términos establecidos en el art. 32 del Texto Refundido de la Ley de Propiedad Intelectual (RDL 1/1996). Para otros usos se requiere la autorización previa y expresa de la persona autora.
    [Show full text]
  • The Wisconsin Integrated Cropping Systems Trial - Sixth Report
    THE WISCONSIN INTEGRATED CROPPING SYSTEMS TRIAL - SIXTH REPORT TABLE OF CONTENTS Prologue ..................................................... Introduction .................................................... ii MAIN SYSTEMS TRIAL -1996 1 . Arlington Agricultural Research Station - 1996 Agronomic Report . 1 2. Lakeland Agricultural Complex - 1996 Agronomic Report .................. 3 3. Weed Seed Bank Changes: 1990 To 1996 ............................ 9 4. Monitoring Fall Nitrates in the Wisconsin Integrated Cropping Systems Trial . 18 5. WICST Intensive Rotational Grazing of Dairy Heifers .................... 26 6. Wisconsin Integrated Cropping Systems Trial Economic Analysis - 1996 ...... 32 WICST SATELLITE TRIALS - 1996 8. Cropping System Three Chemlite Satellite Trial - Arlington, 1995 and 1996 .... 35 9. Corn Response to Commercial Fertilizer in a Low Input Cash Grain System ..... 36 10. WICST On-Farm Cover Crop Research .............................. 38 11 . Summer Seeded Cover Crops - Phase 1, 1996 ........................ 43 12. Improving Weed Control Using a Rotary Hoe .......................... 49 WICST SOIL BIODIVERSITY STUDY - 1996 13. Preliminary Report on Developing Sampling Procedures and Biodiversity Indices 53 14. Soil Invertebrates Associated with 1996 Soil Core Sampling and Residue Decomposition . 66 15. Analysis of Soil Macroartropods Associated with Pitfall Traps in the Wisconsin Integrated Cropping Systems Trial, 1995 ............................ 71 16. Biodiversity of Pythium and Fusarium from Zea mays in different
    [Show full text]
  • Effect of Diet on Development and Reproduction of the Harvestman Phalangium Opilio (Opiliones: Phalangiidae)
    PHYSIOLOGICAL ECOLOGY Effect of Diet on Development and Reproduction of the Harvestman Phalangium opilio (Opiliones: Phalangiidae) 1 CORA M. ALLARD AND KENNETH V. YEARGAN Department of Entomology, University of Kentucky, Lexington, KY 40546 Environ. Entomol. 34(1): 6Ð13 (2005) Downloaded from https://academic.oup.com/ee/article/34/1/6/478711 by guest on 29 September 2021 ABSTRACT The harvestman Phalangium opilio L. is an abundant predator in an array of habitats, including agricultural systems. In these systems, P. opilio has been noted to feed on pest species (e.g., Colorado potato beetle larvae, various aphid species, and lepidopteran eggs). Although the potential importance of P. opilio has been recognized, little is known about this harvestmanÕs development or reproductive biology. We investigated the inßuence of diet on development time, survival, repro- duction, and female longevity. We compared the effects of two diets, Helicoverpa zea (Boddie) eggs and Aphis glycines Matsumura, on development of P. opilio because this predator is known to feed on those prey in soybean agroecosystems. Individuals fed A. glycines from emergence to adulthood suffered from higher mortality, longer development time, and smaller body size than those fed H. zea eggs. Four diet treatments were used in a separate study to test their effects on reproduction: standard laboratory diet (cornmeal, bacon, and H. zea eggs), H. zea eggs only, A. glycines only, and mixed diet (A. glycines and H. zea eggs). A diet of A. glycines alone yielded higher mortality, smaller body size, and lower fecundity than the standard laboratory diet. The presence of A. glycines in a monotypic or mixed diet lengthened the preoviposition period compared with diets without this prey and yielded a smaller Þrst clutch and smaller average clutch sizes compared with the standard laboratory diet.
    [Show full text]
  • Insect Egg Size and Shape Evolve with Ecology but Not Developmental Rate Samuel H
    ARTICLE https://doi.org/10.1038/s41586-019-1302-4 Insect egg size and shape evolve with ecology but not developmental rate Samuel H. Church1,4*, Seth Donoughe1,3,4, Bruno A. S. de Medeiros1 & Cassandra G. Extavour1,2* Over the course of evolution, organism size has diversified markedly. Changes in size are thought to have occurred because of developmental, morphological and/or ecological pressures. To perform phylogenetic tests of the potential effects of these pressures, here we generated a dataset of more than ten thousand descriptions of insect eggs, and combined these with genetic and life-history datasets. We show that, across eight orders of magnitude of variation in egg volume, the relationship between size and shape itself evolves, such that previously predicted global patterns of scaling do not adequately explain the diversity in egg shapes. We show that egg size is not correlated with developmental rate and that, for many insects, egg size is not correlated with adult body size. Instead, we find that the evolution of parasitoidism and aquatic oviposition help to explain the diversification in the size and shape of insect eggs. Our study suggests that where eggs are laid, rather than universal allometric constants, underlies the evolution of insect egg size and shape. Size is a fundamental factor in many biological processes. The size of an 526 families and every currently described extant hexapod order24 organism may affect interactions both with other organisms and with (Fig. 1a and Supplementary Fig. 1). We combined this dataset with the environment1,2, it scales with features of morphology and physi- backbone hexapod phylogenies25,26 that we enriched to include taxa ology3, and larger animals often have higher fitness4.
    [Show full text]