SEX RATIO VARIABILITY OF MUSCIDIFURAX ZARAPTOR (HYMENOPTERA: PTEROMALIDAE)

1979 ◽  
Vol 111 (1) ◽  
pp. 105-109 ◽  
Author(s):  
H. G. Wylie

AbstractFemales of Muscidifurax zaraptor K. & L. produce a smaller percentage of female progeny as the ratio of ovipositing females to hosts (house fly pupae) increases. Delays in oviposition are apparently responsible for the sex ratio change, because they reduce the percentage of fertilized eggs, i.e. female eggs, that the parasites lay. Delays increase in frequency as the parasite:host ratio increases, and result mostly from interference among the ovipositing females; the interference is mostly or entirely physical. Solitary females of M. zaraptor produce slightly fewer though not significantly fewer female progeny when low host densities delay oviposition; more tests would be required to confirm this effect. There is no evidence for differential survival of the male and female parasite larvae on superparasitized hosts.

CORD ◽  
1997 ◽  
Vol 13 (01) ◽  
pp. 34
Author(s):  
Wily A. Baringbing ◽  
Bariyah Baringbing

An experiment was conducted at a coconut pest laboratory at Nita, elevation 250 m, Sikka regency, Flores island, province of East Nusa Tenggara, to study mass production of Chelonus parasite by using Phthorimaea operculella Zeller as its host, in an effort to control the coconut moth, Batrachedra arenosella Walker, biologically. Results of the experiment showed that the parasite could be produced in laboratory by using P. operculella as the host and a 10% solution of honey as food for both parasite and the adult host. A female parasite gave an average of 14 offspning during their lives with a sex ratio of 2.27:1, between male and female. The sex ratio of the same parasite in the field with B. arenosella as its host was 1:1. The incubation period of the parasite in laboratory was 26 days for males and 27 days for females. The sex ratio of the moth in the field as 1: 1.26.


2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Carlos Gustavo da Cruz ◽  
Clarice Diniz Alvarenga ◽  
Patricia Cristina do Carmo Oliveira ◽  
Edileuza dos Reis Souza Conceição ◽  
Zenobia Cardoso dos Santos ◽  
...  

ABSTRACT: The objective of the present study was to evaluate the ratio of Ceratitis capitata larvae/female of Diachasmimorpha longicaudata that results in the increase of parasitism and the production of females in the progeny. We used 8-day-old copulated D. longicaudata females with oviposition parasite experience and third instar larvae of C. capitata from rearing stock maintained at the Laboratory of Biological Control of Universidade Estadual de Montes Claros (Unimontes). Five densities of C. capitata larvae (10, 20, 30, 40, and 50) were offered to parasitoid females that were at five different densities (1, 2, 5, 10, and 15). The larvae were exposed to the parasitoid females by means of “parasitism units” in adapted cages for 1 hour. Sex ratio, percentage of parasitism, and pupal mortality were evaluated. Both host larval density and female parasite density influenced parasitism, female progeny production, and pupal mortality. Higher female production was observed in the progeny in ratios of 1:1 and 2:1 (larvae/females). Ratios above 1:2 reduced the sex ratio, and ratios below 1:1 caused high pupal mortality rates. The females had higher parasitism activity when they were in groups dividing the same space. Equal ratios of Ceratitis capitata larvae and parasitoid females resulted in improved efficiency in progeny females.


1976 ◽  
Vol 108 (11) ◽  
pp. 1267-1274 ◽  
Author(s):  
H.G. Wylie

AbstractFemales of Eupteromalus dubius (Ashm.) oviposit on pupae of cyclorrhaphous Diptera and the larvae develop gregariously as ectoparasites. Details of the life history of E. dubius are described. A progressively lower percentage of female progeny of E. dubius matures as the parasite:host ratio increases. Three mechanisms that may cause this sex ratio change are examined and discussed.


2012 ◽  
Vol 2 (1_suppl) ◽  
pp. s-0032-1319931-s-0032-1319931
Author(s):  
S. Al Rowas ◽  
R. Gawri ◽  
R. Haddad ◽  
A. Almaawi ◽  
L. E. Chalifour ◽  
...  

2016 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.


2018 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.


Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1721-1731 ◽  
Author(s):  
Jesse E Taylor ◽  
John Jaenike

AbstractSeveral empirical studies of sperm competition in populations polymorphic for a driving X chromosome have revealed that Sex-ratio males (those carrying a driving X) are at a disadvantage relative to Standard males. Because the frequency of the driving X chromosome determines the population-level sex ratio and thus alters male and female mating rates, the evolutionary consequences of sperm competition for sex chromosome meiotic drive are subtle. As the SR allele increases in frequency, the ratio of females to males also increases, causing an increase in the male mating rate and a decrease in the female mating rate. While the former change may exacerbate the disadvantage of Sex-ratio males during sperm competition, the latter change decreases the incidence of sperm competition within the population. We analyze a model of the effects of sperm competition on a driving X chromosome and show that these opposing trends in male and female mating rates can result in two coexisting locally stable equilibria, one corresponding to a balanced polymorphism of the SR and ST alleles and the second to fixation of the ST allele. Stochastic fluctuations of either the population sex ratio or the SR frequency can then drive the population away from the balanced polymorphism and into the basin of attraction for the second equilibrium, resulting in fixation of the SR allele and extinction of the population.


2017 ◽  
Vol 3 (2) ◽  
pp. 123
Author(s):  
Dian Novianto ◽  
Budi Nugraha ◽  
Andi Bahtiar

Ikan todak berparuh pendek atau ikan tumbuk atau shortbill spearfish (Tetrapturus angustirostris) merupakan salah satu hasil tangkapan sampingan rawai tuna. Informasi mengenai ikan todak berparuh pendek seperti komposisi ukuran, perbandingan kelamin, dan tingkat kematangan gonadsangat terbatas. Tulisan ini bertujuan untuk menyajikan data dan informasi mengenai aspek biologi ikan todak berparuh pendek yang merupakan hasil tangkapan sampingan dari rawai tuna yang beroperasi di Samudera Hindia. Penelitian ini dilakukan pada bulan September sampai Desember 2008 di perairan Samudera Hindia. Hasil penelitian menunjukan bahwa ikan todak berparuh pendek memiliki kisaran panjang tubuh 135-175 cmLJFL dan modus pada kisaran 155-165 cmLJFL.Perbandingan jenis kelamin ikan jantan dan betina 1:13,5, berdasarkan atas hasil uji chi-square menunjukan bahwa rasio ikan jantan dan betina pada periode penelitian ini tidak seimbang. Pada bulan September ikan todak berparuh pendek betina didominansi oleh tingkat kematangan gonad IIsebesar 66,7%, bulan Oktober oleh tingkat kematangan gonad V sebesar 46,2%, bulan Nopember oleh tingkat kematangan gonad II sebesar 53,3%, sedangkan pada bulan Desember oleh tingkat kematangan gonad III sebesar 42,9%. Pada bulan Nopember sampai Desember terlihat bahwa tingkat kematangan gonad V mulai berkurang, hal ini menunjukan bahwa pada bulan Nopember sampai Desember diduga banyak ikan todak berparuh pendek betina yang sudah memijah. Shortbill Spearfish (Tetrapturus angustirostris) is one of bycatch of tuna longline. Information about shortbill spearfish on the size composition, sex ratio, and maturity stage is still very limited. The objective this paper is to present the data and information about shortbill spearfish which is a bycatch of tuna longline that operated in the Indian Ocean. Research was conducted during September until December 2008 in Indian Ocean. The results showed that the shortbill spearfish have body length about 135-175 cmLJFL and modes in 155-165 cmLJFL. Sex ratio of the male and female was 1:13.5. Based on chi-square test showed that the ratio of male and female in the period of the study was not balanced. In September, the female stage maturity was dominated by level II of 66.7%, October by level V of 46.2%, November by level II of 53.3%, and December by level III of 42.9%. During November until December showed that the maturity stage of level V was decreased, this shows that in this time the female of shortbill spearfish was spawned.


2019 ◽  
Vol 18 (2) ◽  
pp. 87 ◽  
Author(s):  
. Jusmaldi ◽  
Nova Hariani

Biology of the spotted barb Barbodes binotatus (Valenciennes, 1842) in Barambai River, east Kalimantan is unknown. This study aimed to analyses sizes of fish, sex ratio, length-weight relationship and condition factor of the spotted barb. A total of 347 fish samples were collected by several gears in Barambai River from August to October 2017. The results of this research showed that the total length of the fish ranged from 45.67 to 146.01 mm and weight ranged from 1.27-43.34 g. The sex ratio of male and female were 1:1.12. The length-weight equations for males was W = 1x10-5 L3.063, W = 8x10-6L3.108 for females, and W = 9 x 10-6 L3.091 for both sexes. The condition factor (K) for the spotted barb was ranged between 0.826 – 2.214 with mean value of 1.163.  AbstrakBiologi ikan wader bintik dua Barbodes binotatus (Valenciennes, 1842) di Sungai Barambai, Kalimantan Timur belum diketahui. Penelitian ini bertujuan menganalisis ukuran ikan, nisbah kelamin, hubungan panjang bobot, dan faktor kon-disi. Total 347 sampel ikan dikumpulkan dengan menggunakan berbagai alat tangkap di Sungai Barambai dari bulan Agustus sampai Oktober 2017. Hasil penelitian menunjukkan bahwa panjang total ikan berkisar dari 45,67 sampai 146,01 mm dan bobot tubuh berkisar 1,27- 43,34 gram. Nisbah kelamin jantan dan betina 1: 1,12. Model hubungan panjang bobot ikan jantan W = 1x10-5 L3,063, ikan betina W = 8x10-6L3,108,dan keseluruhan jenis ikan W =  9 x 10-6  L3,091. Faktor kondisi (K) ikanwader bintik dua berkisar antara 0,826 - 2,214 dan rata-rata 1,163. 


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