scholarly journals INFLUENCE OF HOST STAGE ON OVIPOSITION, DEVELOPMENT, AND SEX RATIO OF Anagyrus lopezi (DE SANTIS) (HYMENOPTERA: ENCYRTIDAE), A PARASITOID OF THE CASSAVA MEALYBUG, Phenacoccus manihoti MATILE-FERRERO (HEMIPTERA: PSEUDOCOCCIDAE)

2020 ◽  
Vol 20 (2) ◽  
pp. 130-139
Author(s):  
Evie Adriani ◽  
Aunu Rauf ◽  
Pudjianto Pudjianto
Keyword(s):  
Sex Ratio ◽  
Mass Rearing ◽  
Instar Nymph ◽  
Choice Test ◽  
Phenacoccus Manihoti ◽  
Cassava Mealybug ◽  
First Instar ◽  
Immature Development ◽  
Host Stage ◽  
Biased Sex Ratio

Influence of host stage on oviposition, development, and sex ratio of Anagyrus lopezi (De Santis) (Hymenoptera: Encyrtidae), a parasitoid of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae). The parasitoid Anagyrus lopezi (De Santis) (Hymenoptera: Encyrtidae) was introduced from Thailand into Indonesia in early 2014 to control the invasive cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae). Because of the need to produce large numbers of high-quality females, research was conducted in the laboratory to determine host stage preference for A. lopezi on different instars of P. manihoti. Individual female wasps were exposed to first, second, third instar nymphs, and pre-reproductive adult mealybugs. In the no-choice test, the frequency of parasitized hosts and the number of eggs laid per host was significantly higher in second and third instar nymphs as well as adult mealybugs compared to first instar nymphs. In the two-choice test, third instars nymphs and adult mealybugs were the most preferred host for oviposition. Immature development of parasitoids was faster and the ratio of female to male parasitoids was higher following oviposition in second and third instar nymphs and pre-reproductive adult hosts, compared to the first instar nymphs. Our findings indicate that the use of pre-reproductive adults as hosts in a mass-rearing program would be the most productive and fastest way to produce A. lopezi populations with a female-biased sex ratio. Field release of parasitoids should be conducted when the host’s third instar nymph is the most abundant because the period during which preferred and suitable host stages are available would be the longest.

scholarly journals Biologi Stenocranus pacificus Kirkaldy (Hemiptera: Delphacidae) pada tanaman jagung (Zea mays L.) di rumah kasa

2020 ◽  
Vol 17 (2) ◽  
pp. 104
Author(s):  
Dosma Ulina Simbolon ◽  
Maryani Cyccu Tobing ◽  
Darma Bakti
Keyword(s):  
Zea Mays ◽  
Life Cycle ◽  
Sex Ratio ◽  
Zea Mays L ◽  
Instar Nymph ◽  
Fourth Instar ◽  
The Third ◽  
First Instar ◽  
Corn Plants ◽  
North Sumatra

<p><em>Stenocranus pacificus </em>Kirkaldy (Hemiptera: Delphacidae) is destructive pest on corn plants in South Lampung and it has been reported to cause corn damages in North Sumatra. The  objective of this research was to study some aspects biology of <em>S. pacificus</em> on corn plants in screenhouse. The research was conducted by observing the biology of <em>S. pacificus</em> that was reared on corn plants in screenhouse.<em> </em>The results showed that life cycle of <em>S. pacificus </em>was 38–47 (41,60 ± 3,19) days: egg was 9–11 (10,20 ± 0,79) days, the first instar nymph was 3–4 (3,70 ± 0,48) days, the second instar nymph was 3–4 (3,90 ± 0,32) days, the third instar nymph was 3–4 (3,70 ± 0,48) days, the fourth instar nymph was 3–4 (3,80 ± 0,42) days, and the fifth instar nymph was 3–4 (3,60 ± 0,52) days. Age of female was 13–17 (15,30 ± 1,34) days. It was longer than age of male which was 8–12 (10,10 ± 1,20) days. Female could produce 181–214 (197,60 ± 11,64) eggs during its life. The sex ratio was 1:1,98.</p>

Exploration for natural enemies of the cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae), in South America for the biological control of this introduced pest in Africa

1990 ◽  
Vol 80 (4) ◽  
pp. 417-425 ◽  
Author(s):  
B. Löhr ◽  
A.M. Varela ◽  
B. Santos
Keyword(s):  
Natural Enemies ◽  
Mass Rearing ◽  
Phenacoccus Manihoti ◽  
International Institute ◽  
Mato Grosso ◽  
Cassava Mealybug ◽  
Paraguay River ◽  
Introduced Pest ◽  
Mato Grosso Do Sul ◽  
Ibadan Nigeria

AbstractAreas in Argentina, Bolivia, Brazil and Paraguay were searched for the cassava mealybug, Phenacoccus manihoti Matile-Ferrero. The mealybug was located in the Paraguay River basin in the Santa Cruz de la Sierra area of eastern Bolivia, the Mato Grosso do Sul state in South-Western Brazil and in Paraguay east of the Paraguay River. Mealybug populations were extremely low in all areas but there was a period of increase from August to December. Eighteen species of natural enemies were found attacking P. manihoti: the most abundant and also most important were a solitary, internal parasitoid, Epidinocarsis lopezi (DeSantis) (Hymenoptera: Encyrtidae), Hyperaspis notata Mulsant and Diomus spp. (Coleoptera: Coccinellidae), and Ocyptamus spp. (Diptera: Syrphidae). Collections of a closely related mealybug, Phenacoccus herreni Cox & Williams yielded two additional encyrtid parasitoids, Epidinocarsis diversicornis (Howard) and Aenasius sp. nr vexans Kerrich, but they did not survive on P. manihoti. Four parasitoids (E. lopezi, E. diversicornis, Parapyrus manihoti Noyes and Allotropa sp.) and four predators (H. notata, Diomus sp., Sympherobius maculipennis Kimmins, and Exochomus sp.) were sent for quarantine. With the exception of Parapyrus manihoti, all mentioned natural enemy species were forwarded to the International Institute of Tropical Agriculture at Ibadan, Nigeria for mass rearing and subsequent release.

A glyphosate-based herbicide in a free-choice test on parasitism, emergence, and female-biased sex ratio of 10 Trichogrammatidae

2019 ◽  
Vol 127 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Jonas Pereira Pontes ◽  
Germano Leão Demolin Leite ◽  
Edilson Paulo Rodrigues Bispo ◽  
Wagner de Souza Tavares ◽  
Claubert Wagner Guimarães de Menezes ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Free Choice ◽  
Choice Test ◽  
Biased Sex Ratio

scholarly journals Effects of temperature and host stage on the parasitization rate and offspring sex ratio ofAenasius bambawaleiHayat inPhenacoccus solenopsisTinsley

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1586 ◽  
Author(s):  
Juan Zhang ◽  
Jun Huang ◽  
Yaobin Lu ◽  
Tianfeng Xia
Keyword(s):  
Sex Ratio ◽  
Mass Rearing ◽  
Phenacoccus Solenopsis ◽  
Offspring Sex Ratio ◽  
Parasitization Rate ◽  
Offspring Sex ◽  
Laboratory Results ◽  
Host Stage ◽  
Effects Of Temperature ◽  
Temperature Exposure

Temperature and host stage are important factors that determine the successful development of parasitoids.Aenasius bambawaleiHayat (Hymenoptera: Encyrtidae) is a primary parasitoid of the newly invasive mealybug,Phenacoccus solenopsisTinsley (Hemiptera: Pseudococcidae). The effects of temperature on the parasitic characteristics ofA. bambawaleihave seldom been investigated. In the study, we explored the effects of temperature, exposure time, and host stage on the parasitization rate and offspring sex ratio (female to male) ofA. bambawaleiunder laboratory conditions. The laboratory results showed that the successful parasitization rate ofA. bambawaleiincreased with higher temperatures and older host stages. When the parasitoids were exposed to 36 °C for 24 h, the parasitization rate of female adults (52%) was nearly two times that of 3rd instar nymphs. Additionally, heat stress duration and host stage resulted in an increase in the offspring sex ratio ofA. bambawalei. WhenA. bambawaleiwas exposed to 36 °C for 24 h, the offspring sex ratio increased dramatically to 81.78% compared with those exposed for 12 h, and it increased to 45.34% compared with those exposed for 16 h. The offspring sex ratio was clearly higher when the host stage was an adult female mealybug Our findings provide important guidance for the mass rearing and field releases ofA. bambawaleifor the management ofP. solenopsisin the future.

No room for males in caves: Female‐biased sex ratio in subterranean amphipods of the genus Niphargus

2021 ◽  
Author(s):  
Ester Premate ◽  
Špela Borko ◽  
Simona Kralj‐Fišer ◽  
Michael Jennions ◽  
Žiga Fišer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Biased Sex Ratio

Morphology of the first instar nymph of Leucaspis loewi Colvée (Hemiptera: Coccinea: Diaspididae)

2012 ◽  
Vol 81 (1) ◽  
pp. 43-47
Author(s):  
Elżbieta Podsiadło ◽  
Anna Mazurkiewicz
Keyword(s):  
Abdominal Segment ◽  
Instar Nymph ◽  
First Instar ◽  
Campaniform Sensillum ◽  
Anterior Spiracle

Morphology of the first instar nymph of Leucaspis loewi Colvée (Hemiptera: Coccinea: Diaspididae) The first instar nymph of Leucaspis loewi Colvée is redescribed and illustrated. The sex has not been determined. It has 5-segmented antennae, one trilocular disc pore associated with the anterior spiracle, one pair of well-developed lobes, and fimbriate plates on all abdominal segments. Tibia and tarsus are not fused - they are separated from each other by a septum. A campaniform sensillum is always present at the bases of the tarsi. Dorsal submedian setae are present on each abdominal segment 1-7.

Male-biased sex ratio in Argulus canadensis Wilson, 1916 (Crustacea: Branchiura) ectoparasitic on sticklebacks

1989 ◽  
Vol 67 (8) ◽  
pp. 2078-2080 ◽  
Author(s):  
Robert Poulin ◽  
Gerard J. FitzGerald
Keyword(s):  
Salt Marsh ◽  
Sex Ratio ◽  
Laboratory Experiments ◽  
Fish Predation ◽  
Reproductive Behaviour ◽  
Egg Deposition ◽  
Alternative Hypotheses ◽  
Biased Sex Ratio ◽  
The Difference ◽  
Fish Hosts

Females of the ectoparasitic crustacean Argulus canadensis must leave their fish hosts at least temporarily to deposit their eggs on the substrate. To test the hypothesis that this difference in reproductive behaviour between the two sexes could result in male-biased sex ratios on their stickleback hosts, we sampled sticklebacks in tide pools of a Quebec salt marsh from early July to early September 1986. During this period, fish harboured significantly more male than female A. canadensis. Laboratory experiments were done to test two alternative hypotheses offered to explain this biased sex ratio. The first hypothesis was that male A. canadensis were more successful than females in attacking their stickleback hosts; however, we found no differences in attack success on their hosts between the two parasite sexes. The second hypothesis was that sticklebacks ate more female than male A. canadensis. Although males were less vulnerable to fish predation than females, the difference was not significant. We conclude that sexual differences in reproductive behaviour, i.e., egg deposition behaviour of females, can account for the male-biased sex ratio of A. canadensis on sticklebacks.

Female-Biased Sex Ratio at Hatching in the Green Woodhoopoe

The Auk ◽  
1990 ◽  
Vol 107 (4) ◽  
pp. 765-771 ◽  
Author(s):  
J. David Ligon ◽  
Sandra H. Ligon
Keyword(s):  
Sex Ratio ◽  
Biased Sex Ratio

Variably male-biased sex ratio in a marine bird with females larger than males

Oecologia ◽  
1999 ◽  
Vol 118 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Roxana Torres ◽  
Hugh Drummond
Keyword(s):  
Sex Ratio ◽  
Marine Bird ◽  
Biased Sex Ratio

Effects of phytoseiid predators on the sex ratio of the spider mite Panonychus ulmi

1991 ◽  
Vol 69 (1) ◽  
pp. 208-212 ◽  
Author(s):  
Dan L. Johnson ◽  
Heather C. Proctor
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Spider Mite ◽  
Total Population ◽  
Panonychus Ulmi ◽  
Encounter Rate ◽  
Male Mortality ◽  
Adult Sex Ratio ◽  
Biased Sex Ratio ◽  
Male Activity

The effect of predator presence on the adult sex ratio of a spider mite (Panonychus ulmi) was examined in a field experiment. Phytoseiid predators (chiefly Typhlodromus occidentalis) were removed from 32 trees harboring P. ulmi populations, and allowed to remain at natural levels on 32 other trees. Both total population density and proportion of males in the prey population were significantly higher in predator-free trees. Mechanisms that could explain the increase in the proportion of males are examined. The most probable is that greater male activity results in a higher encounter rate between predator and prey, and that subsequent higher male mortality when predators are present exaggerates the female-biased sex ratio. The theoretical effects of sex-biased predation on diplo-diploid and haplo-diploid organisms are discussed.

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