The effect of different diet on life history parameters and growth of Oppia denticulata (Acari: Oribatida: Oppiidae)

2017 ◽  
Vol 22 (5) ◽  
pp. 749 ◽  
Author(s):  
Anna Seniczak ◽  
Stanisław Seniczak ◽  
Mariola Słowikowska ◽  
Zbigniew Paluszak

The effect of different diet on Oppia denticulata was studied during a 4-month laboratory experiment, based on daily observations. This species is known as microphytophagous (i.e. feeding on bacteria and/or fungal hyphae and/or algae), like other species of Oppiidae, but our observations show its wider diet. We tested 11 types of food, including homogenous diet [green algae, lichens, fungi (dry yeasts, Trichoderma viride, Penicillium chrysogenum), nematodes], and combined diet [green algae and nematodes, lichens and nematodes, dry yeasts and nematodes, T. viride and nematodes, P. chrysogenum and nematodes]. The basic population parameters (fertility, mortality, sex ratio), time of development, population growth in four months and body length were compared between all groups. Observations on biology of O. denticulata were also made. The most favourable diet for O. denticulata was a combination of T. viride and nematodes, which allowed the highest population growth (about 50 times higher than the least favourable food, a combination of P. chrysogenum and nematodes), due to highest fertility and shortest development. Good population parameters and largest size were obtained on yeasts (served alone or with nematodes). This species did not do well on P. chrysogenum, probably because it produces penicillin.

2017 ◽  
Vol 22 (5) ◽  
pp. 749
Author(s):  
Anna Seniczak ◽  
Stanisław Seniczak ◽  
Mariola Słowikowska ◽  
Zbigniew Paluszak

The effect of different diet on Oppia denticulata was studied during a 4-month laboratory experiment, based on daily observations. This species is known as microphytophagous (i.e. feeding on bacteria and/or fungal hyphae and/or algae), like other species of Oppiidae, but our observations show its wider diet. We tested 11 types of food, including homogenous diet [green algae, lichens, fungi (dry yeasts, Trichoderma viride, Penicillium chrysogenum), nematodes], and combined diet [green algae and nematodes, lichens and nematodes, dry yeasts and nematodes, T. viride and nematodes, P. chrysogenum and nematodes]. The basic population parameters (fertility, mortality, sex ratio), time of development, population growth in four months and body length were compared between all groups. Observations on biology of O. denticulata were also made. The most favourable diet for O. denticulata was a combination of T. viride and nematodes, which allowed the highest population growth (about 50 times higher than the least favourable food, a combination of P. chrysogenum and nematodes), due to highest fertility and shortest development. Good population parameters and largest size were obtained on yeasts (served alone or with nematodes). This species did not do well on P. chrysogenum, probably because it produces penicillin.


2013 ◽  
Vol 9 (2) ◽  
pp. 20130027 ◽  
Author(s):  
A. Chipman ◽  
E. Morrison

Human mating and reproductive behaviour can vary depending on various mechanisms, including the local sex ratio. Previous research shows that as sex ratios become female-biased, women from economically deprived areas are less likely to delay reproductive opportunities to wait for a high-investing mate but instead begin their reproductive careers sooner. Here, we show that the local sex ratio also has an impact on female fertility schedules. At young ages, a female-biased ratio is associated with higher birth rates in the poorest areas, whereas the opposite is true for the richest areas. At older ages, a female-biased ratio is associated with higher birth rates in the richest, but not the poorest areas. These patterns suggest that female–female competition encourages poorer women to adopt a fast life-history strategy and give birth early, and richer women to adopt a slow life-history strategy and delay reproduction.


2008 ◽  
Vol 29 (2) ◽  
pp. 245-256 ◽  
Author(s):  
Carissa Jones ◽  
Isaac Rojas-González ◽  
Julio Lemos-Espinal ◽  
Jaime Zúñiga-Vega

Abstract There appears to be variation in life-history strategies even between populations of the same species. For ectothermic organisms such as lizards, it has been predicted that demographic and life-history traits should differ consistently between temperate and tropical populations. This study compares the demographic strategies of a temperate and a tropical population of the lizard Xenosaurus platyceps. Population growth rates in both types of environments indicated populations in numerical equilibrium. Of the two populations, we found that the temperate population experiences lower adult mortality. The relative importance (estimated as the relative contribution to population growth rate) of permanence and of the adult/reproductive size classes is higher in the temperate population. In contrast, the relative importance for average fitness of fecundity and growth is higher in the tropical population. These results are consistent with the theoretical frameworks about life-historical differences among tropical and temperate lizard populations.


1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.


Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 413-429
Author(s):  
Ye Ji Lee ◽  
Won Gyu Park

Abstract The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.


1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.


2014 ◽  
Vol 74 (2) ◽  
pp. 493-500
Author(s):  
MLT. Buschini ◽  
CE. Buss

Podium angustifrons Kohl 1902 is a species of solitary wasp which nests in pre-existing cavities, with neotropical distribution in Argentina, Bolivia, Brazil, Colombia, Guyana and French Guyana. The aim of this study was to investigate the nesting biology of P. angustifrons, discussing aspects of their life history. To capture its nests, wooden trap-nests were installed in the Parque Municipal das Araucárias, Guarapuava (PR), Brazil, from January 2003 to April 2009. A total of 29 nests were collected, all during the warmer months. These showed no vestibular and intercalary cells, and their closures were made up of chewed plants and mud mixed with organic materials and resin-coated surfaces, sometimes showing a layer of lichens. The cells were provisioned with various wild species of cockroaches (Chorisoneura sp, Riata sp and Helgaia sp) in the nymph stage and/or adults. The sex ratio was 4.6 females per male, significantly higher that the expected 1:1. Most pre-pupae entered diapause in winter with development time ranging from 187 to 283 days for females and 180 to 283 days for males. Deaths occurred in 41.66% of cells provisioned, 33.33% were attributed to faulty development and 8.33% to Chrysididae.


2010 ◽  
Vol 157 (6) ◽  
pp. 1225-1236 ◽  
Author(s):  
Alexandre N. Zerbini ◽  
Phillip J. Clapham ◽  
Paul R. Wade

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