HOST DISCRIMINATION BY THE APHID PARASITOID APHELINUS ASYCHIS (HYMENOPTERA: APHELINIDAE): WHEN SUPERPARASITISM IS NOT ADAPTIVE

1990 ◽  
Vol 122 (2) ◽  
pp. 363-372 ◽  
Author(s):  
B. Bai ◽  
M. Mackauer
Keyword(s):  
Egg Production ◽  
Acyrthosiphon Pisum ◽  
Host Acceptance ◽  
Parasitoid Species ◽  
Aphid Parasitoid ◽  
Egg Deposition ◽  
Aphelinus Asychis ◽  
Solitary Parasitoid ◽  
Long Time ◽  
Host Rejection

AbstractFemales of the solitary parasitoid Aphelinus asychis Walker discriminated between unparasitized and parasitized second-instar nymphs of the pea aphid, Acyrthosiphon pisum (Harris). Wasps normally avoided superparasitism, except when they were confined with few hosts for a long time. Parasitoid females did not need previous experience with unparasitized aphids (learning) in order to discriminate. They probed with the ovipositor any aphids encountered, a behaviour suggesting that host acceptance and rejection were determined by internal cues. Prolonged ovipositor insertion (>80 s) was correlated with host acceptance and egg deposition, but short insertion times (≤80 s) generally indicated host rejection. Females tended to reject both self- and conspecific-parasitized aphids when provided with two of each kind. We consider hypotheses mat conspecific superparasitism may be adaptive and give examples to show exceptions. We propose that, in egg-limited parasitoid species such as A. asychis, a reproductive strategy based on the regulation of egg production and on oosorption can explain the equal avoidance of self and conspecific superparasitism.

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.

Electrophoretic study of five aphid parasitoid species of the genus Aphidius (Hymenoptera: Braconidae), including evidence for reproductively isolated sympatric populations and a cryptic species

1998 ◽  
Vol 88 (1) ◽  
pp. 3-13 ◽  
Author(s):  
P. Atanassova ◽  
C.P. Brookes ◽  
H.D. Loxdale ◽  
W. Powell
Keyword(s):  
Cryptic Species ◽  
Acyrthosiphon Pisum ◽  
Genetic Relationships ◽  
Pea Aphid ◽  
Parasitoid Species ◽  
Sympatric Populations ◽  
Electrophoretic Study ◽  
Aphid Parasitoid ◽  
Parasitoid Population ◽  
The Uk

AbstractFour polymorphic enzymes (PEP, PGI, PGM and IDH) were separated from adult individuals of five aphid parasitoid species of the genus Aphidius Nees (A. ervi Haliday, A. microlophii Pennacchio & Tremblay, A. eadyi Starý, Gonzalez & Hall, A. picipes Nees and A. urticae Haliday) using horizontal cellulose acetate plate electrophoresis. These markers were used to investigate the genetic relationships, including reproductive isolation and host adaptation/specificity, in laboratory and field populations. Samples were collected from the pea aphid, Acyrthosiphon pisum (Harris) and/or the nettle aphid, Microlophium carnosum (Buckton) in the UK and Bulgaria between 1991 and 1994. Whilst all loci discriminated between some species, PGM discriminated all five species, one species (A. eadyi) bearing two unique alleles (PGMa and PGMc). Aphidius microlophii (from nettle aphid) and A. ervi (from pea aphid), which are difficult to separate morphologically, possessed unique PGM alleles – PGMb and PGMe, respectively. Both parasitoids occur sympatrically, and whilst hybrids heterozygous for PGM were produced in the laboratory (PGMb,e), such genotypes were not observed in the field populations sampled. Hence, the species appear to be reproductively isolated. Most parasitoid populations studied showed mean heterozygote deficiencies per locus (homozygote excess) compared with Hardy-Weinberg expectations. In particular, A. eadyi bearing PGMa alleles were always homozygous whilst additionally, many were homozygous for another allele, PGIb. This is evidence for the existence of one or more morphologically-indistinguishable ‘cryptic’ species occurring sympatrically within European field populations. A dendrogram of relatedness was produced following calculation of Nei's genetic identity coefficient, I from the parasitoid population allele frequency data. All species showed very high similarity between populations at the intraspecific level (>0.9), but fewer interspecific similarities (0.23–0.63). These values compare well with previously published values for Aphidius populations and for other insects.

DISCRIMINATION BETWEEN SELF- AND CONSPECIFIC-PARASITIZED HOSTS IN THE APHID PARASITOID PRAON PEQUODORUM VIERECK (HYMENOPTERA: APHIDIIDAE)

1993 ◽  
Vol 125 (5) ◽  
pp. 957-964 ◽  
Author(s):  
T.P. Danyk ◽  
M. Mackauer
Keyword(s):  
Conditional Probability ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Host Quality ◽  
Host Discrimination ◽  
Aphid Parasitoid ◽  
Type Host ◽  
Host Type ◽  
Solitary Parasitoid ◽  
Preference Tests

AbstractWe evaluated host discrimination and oviposition restraint in the wasp Praon pequodorum Viereck, a solitary parasitoid of the pea aphid, Acyrthosiphon pisum (Harris). In dichotomous preference tests, wasps attacked more unparasitized than equally available parasitized aphids, and more self-parasitized aphids than aphids parasitized by conspecific females. The conditional probability of a female laying an egg into an attacked aphid was independent of the host type. Host discrimination apparently involves a volatile and individual-specific pheromone marker. Females expecting to compete with other (conspecific) wasps for a limited host supply may ensure possession of the host by self superparasitism. Because host examination requires considerably more time than oviposition in P. pequodorum (and eggs contain few resources), it may be adaptive for a female to lay an egg in an examined host regardless of variations in host quality.

AGE-SPECIFIC PATTERN OF HOST DISCRIMINATION BY THE APHID PARASITOID EPHEDRUS CALIFORNICUS BAKER (HYMENOPTERA: APHIDIIDAE)

1990 ◽  
Vol 122 (2) ◽  
pp. 349-361 ◽  
Author(s):  
W. Völkl ◽  
M. Mackauer
Keyword(s):  
Acyrthosiphon Pisum ◽  
Specific Pattern ◽  
Search Rate ◽  
Host Discrimination ◽  
Aphid Parasitoid ◽  
Conspecific Female ◽  
Egg Deposition ◽  
Age Dependent ◽  
Hymenopteran Parasitoids

AbstractThe solitary aphid parasitoid Ephedrus californicus Baker is able to discriminate between unparasitized and parasitized third-instar nymphs of the pea aphid, Acyrthosiphon pisum (Harris). Superparasitism varied with the number of mature eggs (which is age-dependent) present in the ovaries as well as with the number and the quality of any hosts encountered. Conspecific superparasitism varied with wasp age; older females, with a large egg supply, accepted hosts parasitized by a conspecific female if unparasitized aphids were unavailable. Self superparasitism occurred at all ages; it was the least likely behaviour compared with egg deposition in unparasitized and conspecific-parasitized hosts. Prior experience (learning) was not necessary for host discrimination, but it did influence the search rate, which was higher in inexperienced than experienced females. In choice experiments, wasps preferred conspecific- over self-parasitized aphids and thus were able to distinguish between them. It is suggested that oviposition markers vary among conspecific females. The data are discussed with reference to theories about oviposition decisions and progeny allocation in solitary hymenopteran parasitoids.

scholarly journals Trioxys liui Chou & Chou, 1993 (Hymenoptera, Braconidae, Aphidiinae): an invasive aphid parasitoid attacking invasive Takecallis species (Hemiptera, Aphididae) in the Iberian Peninsula

ZooKeys ◽  
2020 ◽  
Vol 944 ◽  
pp. 99-114 ◽  
Author(s):  
Ehsan Rakhshani ◽  
Jose Michelena Saval ◽  
Nicolas Pérez Hidalgo ◽  
Xavier Pons ◽  
Nickolas G. Kavallieratos ◽  
...  
Keyword(s):  
Plant Material ◽  
Local Environment ◽  
Undescribed Species ◽  
Parasitoid Species ◽  
Long Distance ◽  
New Host ◽  
Aphid Parasitoid ◽  
New Association ◽  
Bamboo Plant ◽  
Accidental Introduction

Biological invasion of aphids and other insects has been increased due to long distance commercial transportation of plant material. The bamboo-aphid-parasitoid association is strictly specific and even though it does not develop interactions with the local environment it should be listed as part of the fauna of southwestern Europe. On-going research regarding aphids and their aphidiine parasitoids in Spain has yielded a new association of Trioxys liui Chou & Chou, 1993 with an undescribed species of Takecallis aphids on bamboo, Phyllostachys spp. Here we present the first association of T. liui with aphids of the genus Takecallis that attack bamboos. Trioxys liui is known as a parasitoid of Cranaphis formosana (Takahashi, 1924) and Phyllaphoides bambusicola Takahashi, 1921 on bamboos in China and Russia. The accidental introduction of this parasitoid species to southwestern Europe has been probably realized through transportation of contaminated bamboo plant material. In the current study, a new host association is recorded for T. liui. Its potential to invade other bamboo-associated aphids and the significance of the tritrophic bamboo-aphid-parasitoid interactions in the new environments are also discussed.

scholarly journals Control of mating plug expelling and sperm storage in Drosophila: A gynandromorph- and mutation-based dissection

2019 ◽  
Vol 70 (4) ◽  
pp. 301-311
Author(s):  
János Szabad ◽  
Jing Peng ◽  
Eric Kubli
Keyword(s):  
Egg Production ◽  
Ventral Nerve Cord ◽  
Sperm Storage ◽  
Female Sterility ◽  
Wild Type ◽  
Thoracic Region ◽  
Mating Plug ◽  
Egg Deposition ◽  
Storage Organs ◽  
Reproductive Apparatus

Introduction In this study, we analyzed gynandromorphs with female terminalia, to dissect mating-related female behaviors in Drosophila. Materials and methods We used gynandromorphs, experimentally modified wild-type (Oregon-R) females, and mutant females that lacked different components of the female reproductive apparatus. Results Many of the gynandromorphs mated but did not expel the mating plug (MP). Some of these – with thousands of sperm in the uterus – failed to take up sperm into the storage organs. There were gynandromorphs that stored plenty of sperm but failed to release them to fertilize eggs. Expelling the MP, sperm uptake into the storage organs, and the release of stored sperm along egg production are separate steps occurring during Drosophila female fertility. Cuticle landmarks of the gynandromorphs revealed that while the nerve foci that control MP expelling and also those that control sperm uptake reside in the abdominal, the sperm release foci derive from the thoracic region of the blastoderm. Discussion and conclusion The gynandromorph study is confirmed by analyses of (a) mutations that cause female sterility: Fs(3)Avar (preventing egg deposition), Tm2gs (removing germline cells), and iab-4DB (eliminating gonad formation) and (b) by experimentally manipulated wild-type females: decapitated or cut through ventral nerve cord.

Aphidiinae (Hymenoptera, Braconidae, Aphidiinae) from Slovenia, with descrip-tion of a new Aphidius species

Zootaxa ◽  
2012 ◽  
Vol 3456 (1) ◽  
pp. 36 ◽  
Author(s):  
KATARINA KOS ◽  
STANISLAV TRDAN ◽  
ANDJELJKO PETROVIĆ ◽  
PETR STARÝ ◽  
NICKOLAS G. KAVALLIERATOS ◽  
...  
Keyword(s):  
Host Plants ◽  
Deciduous Forest ◽  
Mediterranean Species ◽  
Parasitoid Species ◽  
Eastern Deciduous Forest ◽  
Aphid Parasitoid ◽  
Faunal Complexes ◽  
Far Eastern ◽  
First Time ◽  
Tamarix Gallica

Over the period 2006–2010, 40 species of primary parasitoids belonging to eleven genera were found and reared from 50 species of host aphids, from a total of 106 host plants collected from 62 localities all around Slovenia. Over 230 tritrophic associations have been reviewed, including four associations which are reported for the first time; Ephedrus plagiator/ Staticobium limonii/ Limonium angustifolium, Praon necans/ Staticobium limonii/ Limonium angustifolium, Aphidius sussi/Delphinobium sp./Aconitum maximum and Ephedrus persicae/Brachyunguis tamaricis/ Tamarix gallica. The parasitoid species from Slovenia have been grouped in seven faunal complexes according to their origin, e.g. 11 species from European deciduous forest, 3 species from Far Eastern deciduous forest, 20 species from Eurasian Steppes, 1 Mediterranean species, 2 species from Holarctic Forest Tundra, 2 species from Boreal Europe, and 1 Nearctic species. Also, a new aphid parasitoid species Aphidius staticobii sp.n. Tomanović and Petrović has been described from the association Staticobium limonii/ Limonium angustifolium.

scholarly journals Assessing natural mortality of Bay of Biscay anchovy from survey population and biomass estimates

2016 ◽  
Vol 73 (2) ◽  
pp. 216-234 ◽  
Author(s):  
Andrés Uriarte ◽  
Leire Ibaibarriaga ◽  
Lionel Pawlowski ◽  
Jacques Massé ◽  
Pierre Petitgas ◽  
...  
Keyword(s):  
Egg Production ◽  
Linear Models ◽  
Production Method ◽  
Natural Mortality ◽  
Bay Of Biscay ◽  
Stock Assessments ◽  
Long Time ◽  
Using Data ◽  
Log Linear ◽  
Firm Evidence

The closure of the anchovy (Engraulis encrasicolus) fishery in the Bay of Biscay between 2005 and 2010 because of low biomass levels provided an opportunity to estimate natural mortality using data from egg (daily egg production method, DEPM) and acoustic surveys implemented for the assessment of this population since 1987. Assuming that natural mortality (M) is constant over time and that catchability in both surveys is equal for all ages, M could be estimated using log-linear models on the series of surveys of population numbers at age and seasonal integrated stock assessments. The analysis suggests M values of around 0.9 for a common natural mortality at all ages. However, we found firm evidence that natural mortality at ages 2 and older (M2+) is markedly higher than at age 1 (M1), which indicates senescent mortality, a possibility suggested a long time ago for this type of short-lived species.

Grazing by the gastropod, Lacuna vincta, in the lower intertidal area at Musquash Head, New Brunswick, Canada

1983 ◽  
Vol 63 (3) ◽  
pp. 725-736 ◽  
Author(s):  
Martin L. H. Thomas ◽  
Frederick H. Page
Keyword(s):  
New Brunswick ◽  
Egg Production ◽  
Algal Species ◽  
Egg Mass ◽  
Intertidal Area ◽  
Mass Distributions ◽  
Lacuna Vincta ◽  
Egg Deposition ◽  
Large Numbers ◽  
The Impact

Lacuna vincta appeared at Musquash Head, New Brunswick, in large numbers from June to August 1981 principally on lower midlittoral and infralittoral fringe Fucus edentatus. The population reached a mean maximum of 280/m2 in June; by mid September the animals had disappeared. The L. vincta grazed heavily and deposited egg masses on Fucus edentatus but little on other species. All fine and filamentous and encrusting algal species and rock were avoided for egg deposition. Egg mass abundance peaked with the population in June with a mean of 180/m2. Mean egg production in June was 83000/m2.Both snail and egg mass distributions were correlated with the percentage cover of F. edentatus, reaching a maximum at 40–75 cm above mean low tide level.The snails ranged in length from 2–7 mm, consisting of three cohorts from different larval settlements. Growth was rapid in July averaging 0·6 mm/month slowing later.The food plant Fucus edentatus showed a heavy impact of the herbivore. Weight reductions attributable to grazing rose from 56 % in June to 79 % in August and grazed plants tended to thicken rather than elongate with growth. Grazing removed about 79 % of the net production of F. edentatus which averaged 61 g dry wt/m2/day. The impact of the L. vincta population on F. edentatus seems extraordinarily severe.

Sign in / Sign up

Export Citation Format

Share Document