Intraspecific larval competition in two solitary parasitoids, Apoanagyrus (Epidinocarsis) lopezi and Leptomastix dactylopii

1996 ◽  
Vol 81 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Joan Baaren ◽  
Jean-Pierre Nenon
Keyword(s):  
Epidinocarsis Lopezi ◽  
Larval Competition ◽  
Leptomastix Dactylopii

Female antennal sensilla of Epidinocarsis lopezi and Leptomastix dactylopii (Hymenoptera: Encyrtidae), parasitoids of pseudococcid mealybugs

1996 ◽  
Vol 74 (4) ◽  
pp. 710-720 ◽  
Author(s):  
Joan van Baaren ◽  
Roger Barbier ◽  
Jean-Pierre Nénon
Keyword(s):  
Electron Microscopy ◽  
Antennal Sensilla ◽  
Host Discrimination ◽  
Ecological Context ◽  
Epidinocarsis Lopezi ◽  
Olfactory Sensilla ◽  
Transmission Electron ◽  
Different Types ◽  
Ultrathin Sections ◽  
Leptomastix Dactylopii

Antennal sensilla were compared in females of two encyrtid Hymenoptera, Epidinocarsis lopezi and Leptomastix dactylopii, parasitoids of adults and larvae of Pseudococcidae. The external morphology of these sensilla was studied using scanning electron microscopy and their ultrastructure observed under transmission electron microscopy using ultrathin sections. Female antennae have seven different types of sensilla, morphologically very similar in the two species: trichoid sensilla, which are putative mechanosensilla, sensilla chaetica types 1 and 2, which are presumably contact chemosensilla, and sensilla chaetica types 3 and 4, basiconic sensilla, and placoid sensilla, which are all presumed to be olfactory sensilla. Sensilla chaetica types 2 and 4 are thought to be directly involved in host discrimination. The only differences between the two species are in the number and distribution of some types of sensilla. These differences might be related to the varied tritrophic ecological context of the two species rather than to their similar biology.

scholarly journals Larval competition risk shapes male–male competition and mating behavior in an anuran

2016 ◽  
pp. arw100 ◽  
Author(s):  
Hugo Cayuela ◽  
Thierry Lengagne ◽  
Bernard Kaufmann ◽  
Pierre Joly ◽  
Jean-Paul Léna
Keyword(s):  
Mating Behavior ◽  
Male Competition ◽  
Larval Competition

scholarly journals Age-dependent intra-specific competition in pre-adult life stages and its effects on adult population dynamics

2015 ◽  
Vol 27 (1) ◽  
pp. 131-156
Author(s):  
RONGSONG LIU ◽  
GERGELY RÖST ◽  
STEPHEN A. GOURLEY
Keyword(s):  
Disease Transmission ◽  
Adult Population ◽  
Adult Life ◽  
Life Stages ◽  
Larval Competition ◽  
Amphibian Species ◽  
Age Dependent ◽  
Age Structured ◽  
Delay Differential ◽  
Boundedness And Persistence

Intra-specific competition in insect and amphibian species is often experienced in completely different ways in their distinct life stages. Competition among larvae is important because it can impact on adult traits that affect disease transmission, yet mathematical models often ignore larval competition. We present two models of larval competition in the form of delay differential equations for the adult population derived from age-structured models that include larval competition. We present a simple prototype equation that models larval competition in a simplistic way. Recognising that individual larvae experience competition from other larvae at various stages of development, we then derive a more complex equation containing an integral with a kernel that quantifies the competitive effect of larvae of ageāon larvae of agea. In some parameter regimes, this model and the famous spruce budworm model have similar dynamics, with the possibility of multiple co-existing equilibria. Results on boundedness and persistence are also proved.

scholarly journals Interplay of population genetics and dynamics in the genetic control of mosquitoes

2014 ◽  
Vol 11 (93) ◽  
pp. 20131071 ◽  
Author(s):  
Nina Alphey ◽  
Michael B. Bonsall
Keyword(s):  
Population Genetics ◽  
Overlapping Generations ◽  
Large Scale ◽  
Genetic Model ◽  
Homing Endonuclease ◽  
Wild Type ◽  
Larval Competition ◽  
Selfish Genetic Elements ◽  
Fitness Effects ◽  
Ecological Aspects

Some proposed genetics-based vector control methods aim to suppress or eliminate a mosquito population in a similar manner to the sterile insect technique. One approach under development in Anopheles mosquitoes uses homing endonuclease genes (HEGs)—selfish genetic elements (inherited at greater than Mendelian rate) that can spread rapidly through a population even if they reduce fitness. HEGs have potential to drive introduced traits through a population without large-scale sustained releases. The population genetics of HEG-based systems has been established using discrete-time mathematical models. However, several ecologically important aspects remain unexplored. We formulate a new continuous-time (overlapping generations) combined population dynamic and genetic model and apply it to a HEG that targets and knocks out a gene that is important for survival. We explore the effects of density dependence ranging from undercompensating to overcompensating larval competition, occurring before or after HEG fitness effects, and consider differences in competitive effect between genotypes (wild-type, heterozygotes and HEG homozygotes). We show that population outcomes—elimination, suppression or loss of the HEG—depend crucially on the interaction between these ecological aspects and genetics, and explain how the HEG fitness properties, the homing rate (drive) and the insect's life-history parameters influence those outcomes.

scholarly journals Oviposition site attraction of Aedes albopictus to sites with conspecific and heterospecific larvae during an ongoing invasion in Medellín, Colombia

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Talya Shragai ◽  
Laura Harrington ◽  
Catalina Alfonso-Parra ◽  
Frank Avila
Keyword(s):  
Open Field ◽  
Aedes Albopictus ◽  
Competitive Exclusion ◽  
Oviposition Preference ◽  
Ecological Niches ◽  
Low Density ◽  
Larval Competition ◽  
Field Cage ◽  
Main Hypothesis ◽  
Oviposition Sites

Abstract Background Aedes aegypti and Aedes albopictus are two globally invasive vectors with similar ecological niches. Encounters between them can result in either competitive exclusion or stable co-existence, but it is unclear what drives these variable outcomes. Larval competition in favor of Ae. albopictus is a main hypothesis for the competitive exclusion of Ae. aegypti observed in some regions. However, the role of oviposition preference in determining the degree of competitive larval interactions in the field is not well understood. In this study, we used a combination of mark-release-recapture methods with ovitraps in the open-field and a semi-field cage to test whether gravid Ae. albopictus seek oviposition sites in response to the presence, species, and density of either conspecific or heterospecific Ae. aegypti larvae in the aquatic habitat. We conducted our study in Medellín, Colombia, where Ae. aegypti is a long-term resident and Ae. albopictus is a recent invader. Results In the open-field and semi-field cage experiments, gravid Ae. albopictus showed strong preference for ovitraps with larvae over those without. They consistently preferred ovitraps with higher density of conspecific (Ae. albopictus) larvae and low density of heterospecific (Ae. aegypti) larvae over traps with no larvae or high density of heterospecific (Ae. aegypti) larvae. In the semi-field cage experiment, traps with low density of Ae. albopictus were not preferred more or less than any other trap, but in the open-field experiment they were preferred over traps without larvae. Conclusions We demonstrate, through open-field and semi-field cage experiments, that Ae. albopictus are more attracted to oviposition sites with larvae and that the combination of species and density of larvae influence attraction. This demonstrated preference could increase interspecific larval competition as Ae. albopictus actively seek containers with conspecific and heterospecific larvae. Any resulting competition with Ae. aegypti may favor one species over the other and alter the distribution or abundance of both. Because these species vary in vectorial capacity and insecticide resistance, effects of interspecific competition could ultimately impact arbovirus transmission rates and the success of vector control efforts.

MELANIZATION OF EGGS AND LARVAE OF THE PARASITOID, EPIDINOCARSIS LOPEZI (DE SANTIS) (HYMENOPTERA: ENCYRTIDAE), BY THE CASSAVA MEALYBUG, PHENACOCCUS MANIHOTI MATILE-FERRERO (HOMOPTERA: PSEUDOCOCCIDAE)

1988 ◽  
Vol 120 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Daniel J. Sullivan ◽  
Peter Neuenschwander
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Control Agent ◽  
Phenacoccus Manihoti ◽  
Defense Reaction ◽  
Epidinocarsis Lopezi ◽  
Cassava Mealybug ◽  
Major Pest ◽  
Eggs And Larvae ◽  
Host Tissues

AbstractThe encyrtid wasp Epidinocarsis lopezi (De Santis) has been introduced into Africa as a biological control agent against the cassava mealybug Phenacoccus manihoti Matile-Ferrero. This host has a defense reaction against the immature parasitoid that involves encapsulation and melanization. Under laboratory conditions, 37.5% of once-stung cassava mealybugs had been parasitized, as indicated by eggs and larvae of the parasitoid in dissected hosts. Of these parasitized cassava mealybugs, 89.6% contained melanized particles (egg, partially melanized larva, internal host tissues, exoskeleton wound scars). Some of the parasitoid larvae were only partially melanized, and either freed themselves from the melanized capsule or else shed it at the next molt. By the 3rd day of their development only 12.5% were completely melanized. In cassava mealybugs with melanized host tissue but no living parasitoid, the survival of the host was not affected by the melanization. The mealybug itself sometimes shed black particles at the next molt and these were found attached to the cast skins. When superparasitized in the laboratory, 68.6% of twice-stung cassava mealybugs contained parasitoids. Mummies collected from a field experiment showed that melanization rates of mummies increased with increasing parasitization rates. Thus, melanization in the cassava mealybug was commonly triggered when E. lopezi oviposited, but this defense reaction was mostly ineffective, permitting the introduced parasitoid to be a successful biological control agent in Africa against the cassava mealybug, a major pest on this important food crop.

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