Host discrimination and larval competition in the aphid parasite Ephedrus californicus

1986 ◽  
Vol 41 (3) ◽  
pp. 243-254 ◽  
Author(s):  
F. J. Chow ◽  
M. Mackauer
Keyword(s):  
Host Discrimination ◽  
Larval Competition ◽  
Aphid Parasite

CONSPECIFIC SUPERPARASITISM IN TWO PARASITOID WASPS, APHIDIUS ERVI HALIDAY AND APHELINUS ASYCHIS WALKER: REPRODUCTIVE STRATEGIES INFLUENCE HOST DISCRIMINATION

1991 ◽  
Vol 123 (6) ◽  
pp. 1229-1237 ◽  
Author(s):  
B. Bai
Keyword(s):  
Reproductive Strategies ◽  
Acyrthosiphon Pisum ◽  
Aphidius Ervi ◽  
Parasitoid Wasps ◽  
Host Discrimination ◽  
Larval Competition ◽  
Parasitoid Species ◽  
Aphid Parasitoid ◽  
Aphelinus Asychis ◽  
Physiological Suppression

AbstractConspecific host discrimination and larval competition in two aphid parasitoid species were studied in the laboratory using the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), as a host. Aphidius ervi Haliday (Hymenoptera: Aphidiidae) used internal host cues to discriminate between unparasitized and conspecific parasitized hosts. When only parasitized hosts were available, females oviposited into recently parasitized ones where their progeny had a good chance to survive, but rejected those parasitized ≥24 h earlier where their offspring normally died. Competitions occurred only after both eggs had hatched. Larvae eliminated supernumeraries by means of physical combat and physiological suppression. In Aphelinus asychis Walker (Hymenoptera: Aphelinidae), factors, or changes in host internal condition, associated with hatching of the first egg resulted in suppression of conspecific competitors which could be in either larval or egg stage. The older larvae always won competitions through physiological means. A wasp’s oviposition decision is shown to be influenced by the probability of its progeny’s survival. Species that have different reproductive strategies may respond differently to identical host conditions.

scholarly journals Volatile metabolites of willows determining host discrimination by adult Plagiodera versicolora

2021 ◽  
Author(s):  
Jiahao Ling ◽  
Xiaoping Li ◽  
Guo Yang ◽  
Tongming Yin
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Insect Pests ◽  
Leaf Beetle ◽  
Gas Chromatography Mass Spectrometry ◽  
Host Discrimination ◽  
Plagiodera Versicolora ◽  
Volatile Metabolites ◽  
Hexenyl Acetate ◽  
Volatile Organic

AbstractPlagiodera versicolora Laicharting is a highly damaging leaf beetle foraging on willow leaves. In willow germplasm collections, observation has shown that Salix suchowensis Cheng was severely foraged by this leaf beetle while Salix triandra L. was damage free or only slightly damaged. Results of olfactometer bioassays show that the headspace volatiles from leaves of S. triandra significantly repelled adult beetles, suggesting that this species produces volatile repellents against P. versicolora. S. suchowensis had no effect on the beetles. Gas chromatography-mass spectrometry was carried out to profile the headspace volatile organic compounds and 23 compounds from leaves of the alternate species in significantly different concentrations were detected. The effects of 20 chemical analogs on host discrimination were examined. Olfactory response to these chemicals showed that o-cymene, a S. suchowensis specific constituent, significantly attracted adult P. versicolora. In contrast, cis-3-hexenyl acetate, a constituent concentrated more in S. triandra than in S. suchowensis, significantly repelled beetles. Mixing o-cymene and cis-3-hexenyl acetate in comparable concentrations as in the volatiles of S. suchowensis demonstrated that the latter could mask the attracting effect of the former, causing a neutral response by adult beetles to leaves of S. suchowensis against clean air. In addition, chemical analogs have the same effect as plants when resembling volatile organic compounds in real samples. Two volatile metabolites were detected triggering host discrimination by one of the most damaging insect pests to host and non-host willows. The two metabolites are of considerable potential for use as olfactory signs in managing the beetles.

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.

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