Biology and field performance ofGryon clavigrallae(Hymenoptera: Scelionidae), an egg parasitoid ofClavigrallaspp. (Hemiptera: Coreidae) in India

2000 ◽  
Vol 90 (3) ◽  
pp. 253-263 ◽  
Author(s):  
J. Romeis ◽  
T.G. Shanower ◽  
K. Madhuri
Keyword(s):  
Sex Ratio ◽  
Cluster Size ◽  
Host Density ◽  
Field Performance ◽  
Egg Parasitoid ◽  
Developmental Threshold ◽  
Adult Females ◽  
Threshold Temperatures ◽  
Cluster Density ◽  
Host Deprivation

AbstractThe biology and impact ofGryon clavigrallaeMineo, an egg parasitoid ofClavigralla scutellarisSpinola andC. gibbosa(Westwood), was investigated. The calculated developmental threshold temperatures for females and males were 15.6°C and 15.8°C, respectively. Emergence exceeded 94% at temperatures between 22 and 30°C. Adult females lived on average 28–96 days when fed with honey. Without food, adults lived < 6 days. Mean fecundity was 56.4 eggs per female. A significant trend of lower fecundity after longer periods of host deprivation was observed.Gryon clavigrallaefemales successfully oviposited in host eggs of all ages though eggs < 4 days old were preferred. Total host handling times were significantly longer onC. gibbosaeggs (23.5 min) than onC. scutellariseggs (12.0 min). Females readily distinguished parasitized from non-parasitized host eggs. Superparasitism was observed when few or no unparasitized eggs were available. Eggs of the twoClavigrallaspecies can be separated by surface structure and condition after eclosion.Clavigralla scutellarislaid significantly larger egg clusters thanC. gibbosa(19.9 versus 10.5 eggs per cluster).Gryon clavigrallaewas present as soon as the firstClavigrallaspp. egg clusters were found on pigeonpea. The percentage of egg clusters parasitized increased early in the season with egg cluster density and remained high (up to 83%) despite fluctuations in host density. Overall,G. clavigrallaeparasitized 40 and 58% ofC. gibbosaandC. scutellariseggs. The percentage of egg clusters parasitized and the number of eggs parasitized per cluster increased significantly with egg cluster size. The overall parasitoid sex ratio was highly female biased but varied with the number of eggs parasitized per cluster.

scholarly journals Nisbah kelamin dan pola peletakan telur parasitoid Trichogramma chilotraeae Nagaraja & Nagarkatti (Hymenoptera: Trichogrammatidae) pada berbagai jumlah inang

2017 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Hasriyanty Hasriyanty ◽  
Damayanti Buchori ◽  
Pudjianto Pudjianto
Keyword(s):  
Sex Ratio ◽  
Laboratory Condition ◽  
Host Density ◽  
Egg Parasitoid ◽  
Ratio Increase ◽  
Female Progeny ◽  
Female Parasitoid

The objective of the research was to study sex ratio and oviposition sequence of egg parasitoid Trichogramma chilotraeae in relation with host density under laboratory condition. Parasitoid response with respect to oviposition sequence was examined by exposing five different host (egg) densities: 3, 6, 12, 24 and 48 on female parasitoids T. chilotraeae. Results showed that in general, female parasitoid laid its female progeny at the beginning of oviposition sequence. Host density was found to have a strong effect on sex ratio. Sex ratio increase with increasing of  host number.

Studies in Ovipositional Behaviour and Control of Sex in Aphytis Melinus Debach, a Parasite of California Red Scale, Aonidiella Aurantii (Mask.).

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
I Abdelrahman
Keyword(s):  
Sex Ratio ◽  
Host Density ◽  
Adult Emergence ◽  
The Body ◽  
Maturation Stage ◽  
Aphytis Melinus ◽  
Egg Maturation ◽  
Mean Size ◽  
Accepted Practice ◽  
And Control

The growing adult female red scale was the most preferred stage for A. melinus, followed by the second growing instar and lastly the male prepupa. The numbers of scale parasitized, the total of eggs laid, the number of eggs per scale, sex ratio and size of the parasites produced were all ranked in the same order. The mean size of parasites produced within the third instar decreased as the number of parasites per host increased. In the absence of the preferred host stages, female A. melinus laid readily in the unpreferred stages. In both A. melinus and A, chrysomphali it was noted that in multi- parasitism pupation, pupal development and adult emergence of all parasites in one host were synchronized. In A. melinus the sex and number of eggs laid per host are influenced by the host's size and quality. When A. melinus laid more than one egg in one host, it laid female eggs first and male eggs later; apparently the spermatheca goes through a period of fatigue, and is incapable of delivering sperm to the eggs descending the oviduct. Sex ratio decreases with increase in number of parasites per host and density of parasite population relative to hosts. The deposition of parasite eggs in a host by one female was observed during a short cycle of oviposition. A. melinus laid its eggs both 'above' and 'below' the body of the scale, whereas A. chrysomphali did so exclusively 'below'. In young mated A. melinus, eggs laid above the body of the scale were females and those below were males, but in old mated females all eggs, wherever laid, were male. Host development stops as soon as a parasite egg is laid. A. melinus avoids laying eggs in already parasitized hosts. The stages of red scale were ranked according to the percentage of mutilated individuals as: first moult (most mutilated), second instar, first instar, third instar, male prepupa and male pupa; second-moult females, egg-maturation stage and crawler-producing stage were unmutilated. A. melinus sometimes partitions her clutch of eggs into two hosts, particularly when host density is high. Partitioning in A. melinus may substitute for the generally accepted practice of super- parasitism, which would not be appropriate because the parasite is able to distinguish between parasitized and unparasitized hosts, is able to sense host density and to distribute her progeny on available hosts. Partitioning is advantageous for biological control. Behaviour of oviposition, mutilation and mutilation feeding in A. melinus are described in detail.

The effect of leguminous plant species onCallosobruchus maculatus(Coleoptera: Bruchidae) and its egg parasitoidUscana lariophaga(Hymenoptera: Trichogrammatidae)

1998 ◽  
Vol 88 (1) ◽  
pp. 93-99 ◽  
Author(s):  
A. van Huis ◽  
M. de Rooy
Keyword(s):  
Sex Ratio ◽  
Plant Species ◽  
Nutritional Quality ◽  
Development Time ◽  
Callosobruchus Maculatus ◽  
Egg Parasitoid ◽  
The Other ◽  
Leguminous Plant ◽  
Trade Off ◽  
Storage Pest

AbstractThe performance of the egg parasitoidUscana lariophagaSteffan was studied when reared on eggs of the bruchid storage pest,Callosobruchus maculatus(Fabricius) developing in seeds of cowpea, chickpea and pigeonpea. The beetle laid more and larger eggs on pigeonpea than on cowpea and chickpea, indicating that there was not a trade-off between number and size of the eggs. The bruchid larvae reared on pigeonpea exhibited a longer development time and a higher mortality than those reared on cowpea and chickpea. The resulting males weighed less than those reared on cowpea and chickpea. The trichogrammatidU. lariophagaparasitized more eggs whenC. maculatuswas reared on chickpea than when reared on the other hosts. Parasitoid larvae developed slowest and had the highest mortality in eggs ofC. maculatusreared on pigeonpea compared to those reared on cowpea and chickpea; the sex ratio (% of females) of the resulting adults was also higher. The high mortality and long development time ofC. maculatusreared on pigeonpea indicated that this legume was less favourable toC. maculatusthan chickpea or cowpea. This was probably also true for the parasitoid since the mortality was higher and development longer in eggs ofC. maculatusreared on pigeonpea compared to those reared on cowpea and chickpea. Therefore, when host eggs were larger and of lower nutritional quality, the proportion of female egg parasitoids was greater.

scholarly journals Response of a remnant marmot population to habitat enhancement yields insights into marmot ecology

2020 ◽  
Vol 101 (3) ◽  
pp. 658-669
Author(s):  
Melissa J Reynolds-Hogland ◽  
Alan B Ramsey ◽  
August T Seward ◽  
Kristine L Pilgrim ◽  
Cory Engkjer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Young Population ◽  
Marmota Flaviventris ◽  
Livestock Management ◽  
Adult Females ◽  
Capture Recapture ◽  
Geographic Expansion ◽  
Age Structured ◽  
Habitat Enhancement ◽  
Remnant Population

Abstract We evaluated the response of a remnant population of yellow-bellied marmots (Marmota flaviventris) to targeted habitat enhancement in an ecological system that had been degraded during ~100 years of intensive livestock management, including marmot eradication. We used capture-recapture data and a novel use of a multistate framework to evaluate geographic expansion of the marmot population pre- and post-habitat enhancement. We also estimated age-structured survival, reproduction, and sex ratios. The marmot population appeared to respond positively to new habitat opportunities created by habitat enhancement: the number of marmots captured increased from three marmots pre-habitat enhancement to 54 (28 adults and yearlings, 26 young) post-habitat enhancement at the end of the study. Marmots expanded geographically by transitioning into habitat-enhanced areas, and adult females occupied and reproduced in all habitat-enhanced areas. The sex ratio of the young population in 2019 was strongly female-biased, which may have been influenced by poor body condition of breeding females owing to unusually prolonged snow cover that year. Adult and yearling survival were within the range of that reported for colonial adults and yearlings in Colorado. Our results suggest that active habitat enhancement can assist in the recovery of marmot populations in systems where marmots historically existed.

scholarly journals Description and Biological Studies of a New Species of Metaphycus Mercet, 1917 (Hymenoptera: Encyrtidae), A Parasitoid of Capulinia linarosae Kondo & Gullan

2019 ◽  
Vol 11 ◽  
pp. 117954331985796
Author(s):  
Dorys T Chirinos ◽  
Takumasa Kondo
Keyword(s):  
Sex Ratio ◽  
Insect Pest ◽  
Morphological Characteristics ◽  
Psidium Guajava ◽  
Adult Longevity ◽  
Single Male ◽  
Adult Females ◽  
Biological Studies ◽  
Control Programmes ◽  
Baseline Information

The guava cottony scale, Capulinia linarosae Kondo & Gullan (Hemiptera: Eriococcidae), is an important pest of guava, Psidium guajava L. (Myrtaceae) in northern Colombia and Venezuela. A species of Metaphycus (Hymenoptera: Encyrtidae) is the only known primary parasitoid associated with this insect pest. The parasitoid is herein described as M. marensis Chirinos & Kondo, sp. nov., based on morphological characteristics of the adult female and male. Biological studies on adult longevity, fecundity, host preference, and sex ratio were conducted. The maximum longevity of the female and the male were 8.0 and 6.5 days, respectively, when fed with diluted honey. On average, a fed mated female laid approximately 40 eggs. Adult females of M. marensis were shown to prefer to parasitize 11- to 15-day-old adult females of C. linarosae and do not parasitize first-instar nymphs of the host eriococcid. The female-to-male sex ratio of the parasitoid was 2.24: 1. When ovipositing females of M. marensis were given only small-sized individuals (second-instar nymphs) of C. linarosae, generally the resulting progeny was a single male wasp. This parasitoid species has arrhenotokous reproduction and is a facultative gregarious parasitoid. These results show a short adult longevity, as well as a relatively low fecundity of the female compared with studies conducted on other Metaphycus species. This study provides essential baseline information for future biological control programmes for C. linarosae.

3.5 SUPPRESSION OF SPRUCE BUDWORM POPULATIONS BY TRICHOGRAMMA MINUTUM RILEY, 1982–1986

1990 ◽  
Vol 122 (S153) ◽  
pp. 56-81 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace ◽  
G. Howse ◽  
J. Meating
Keyword(s):  
Choristoneura Fumiferana ◽  
Host Density ◽  
Spruce Budworm ◽  
Mass Rearing ◽  
Egg Parasitoid ◽  
Curvilinear Relationship ◽  
Egg Masses ◽  
Trichogramma Minutum ◽  
Egg Parasitism ◽  
Release Timing

AbstractThe ability of the egg parasitoid, Trichogramma minutum Riley, to suppress outbreak populations of the spruce budworm, Choristoneura fumiferana (Clemens), was studied annually near Hearst, Ont., from 1982 through 1986. Timing of broadcast parasitoid-releases was linked to spruce budworm moth emergence and oviposition. These phenological relationships were predicted from a regression based on larval development at least 2 weeks before expected emergence; this allowed sufficient time to regulate (program) parasitoid emergence during mass-rearing. Emergence of caged spruce budworm adults was used to monitor moth eclosion in the field. Pheromone traps provided daily information on the activity of male moths and helped to synchronize the parasitoid releases with spruce budworm oviposition. Information on parasitoid activity was obtained from sentinel (laboratory-reared) and naturally occurring spruce budworm egg masses. A curvilinear relationship between the rate of parasitoid release and parasitism of sentinel egg masses was developed. Two parasitoid releases, 1 week apart, early in the oviposition period of spruce budworm, significantly increased parasitism of host eggs by 14–83% and reduced larval populations correspondingly from 42 to 82%. Single releases were less effective and increased parasitism by 0.3–52% (single ground release, 1986). Two parasitoid releases, combined with a spring application of Bacillus thuringiensis Berliner to larval populations, was the most effective strategy and resulted in 83% egg parasitism and 93% larval reduction. Release rates greater than 12–16 × 106 ♀ ♀ T. minutum per hectare were not warranted based on impact and costs. The effects of release timing, weather, host density, and parasitoid quality on the future successful use of T. minutum are discussed.

3.2 GROUND SYSTEMS FOR RELEASING TRICHOGRAMMA MINUTUM RILEY IN PLANTATION FORESTS

1990 ◽  
Vol 122 (S153) ◽  
pp. 31-37 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace
Keyword(s):  
Sex Ratio ◽  
Point Source ◽  
Ground Level ◽  
Egg Parasitoid ◽  
Forest Stands ◽  
Plantation Forests ◽  
Trichogramma Minutum ◽  
Two Systems ◽  
Ground Systems

AbstractTwo systems for releasing the egg parasitoid, Trichogramma minutum Riley, from ground level in forest stands are described: (1) a gridded point-source release using parasitized host eggs attached to cards, and (2) a hand-held leafblower distributing parasitized eggs in bulk. Neither technique affected the emergence of the parasitoids released. Parasitoids emerging from eggs released in bulk had a similar sex ratio, longevity, and fecundity to those not released. Both methods of ground release achieved uniform parasitoid distribution and resulted in levels of parasitism similar to those achieved with aerial releases. Parasitism was greater in the mid- to upper canopy of trees than in the lower canopy. The difficulties associated with each technique and its comparative usefulness in experimental and operational programs are discussed.

Aethiophenax mycetophagi sp. nov. (Acari: Trombidiformes:  Acarophenacidae), an egg parasitoid of Mycetophagus quadripustulatus (Coleoptera: Mycetophagidae) from Iran

2017 ◽  
Vol 22 (4) ◽  
pp. 541 ◽  
Author(s):  
Elham Arjomandi ◽  
Hamidreza Hajiqanbar ◽  
Omid Joharchi
Keyword(s):  
New Species ◽  
Egg Parasitoid ◽  
Mazandaran Province ◽  
Northern Iran ◽  
World Species ◽  
Adult Females ◽  
The World ◽  
Oyster Mushrooms ◽  
A New Species

A new species of the genus Aethiophenax Mahunka, 1981 (Acari: Prostigmata: Acarophenacidae), A. mycetophagi Arjomandi and Hajiqanbar sp. nov., is described and illustrated based on adult females. Mites were collected from the beneath elytra of hairy fungus beetles, Mycetophagus quadripustulatus (Linnaeus, 1761) (Col.: Tenebrionoidea: Mycetophagidae) grazing on oyster mushrooms on a bough of a tree in Mazandaran province, northern Iran. The new species, as fourth representative of the genus, is characterized by all dorsal setae thin and relatively long (26–35) in comparison with those of congeners; all ventral setae thin, setae 2a longest and 1b shortest of venter of idiosoma; tibiotarsus I with solenidion φ slightly clavate and as long as ω; tarsi II with seta pl” modified and spine-like; genu III with two setae (l’ and v’). A key to the world species of the genus is also provided. 

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