Antennoseius (Vitzthumia) janus n.sp. (Acari: Ascidae), a mesostigmatic mite exhibiting adult female dimorphism

1989 ◽  
Vol 67 (5) ◽  
pp. 1291-1310 ◽  
Author(s):  
Evert E. Lindquist ◽  
David Evans Walter
Keyword(s):  
Sex Ratio ◽  
Adult Female ◽  
Generation Time ◽  
Egg Production ◽  
Low Density ◽  
Adult Males ◽  
Adult Females ◽  
As Species ◽  
Single Animal ◽  
The Impact

All instars of Antennoseius janus n.sp are described. Adult females occur as two distinct morphs, a nondispersing female with granular soft integument, barbed dorsal setae, emarginated opisthonotal shield, and fully developed sternal shield, and a dispersing female with smooth soft integument, nearly smooth dorsal setae, entire opisthonotal shield, and reduced sternal shield. Granular morph females begin egg production within 3 days of mating; however, smooth morph females delay reproduction for many weeks, apparently to disperse. Adult males and immatures have a granular soft integument and barbed setae similar to the granular morph females. Females produced in single animal or low density cultures (less than six individuals per culture) with excess food are granular morphs, whereas in more crowded cultures 5–100% of the maturing females are smooth morphs. This is the first example of adult female dimorphism confirmed experimentally for any family of mites in the entire order Mesostigmata of the Acari. The impact of this phenomenon on taxonomic concepts in the genus Antennoseius is discussed. A key is included, which distinguishes between the genera Anystipalpus Berlese, 1911 and Antennoseius Berlese, 1916, between the subgenera Antennoseius s.str. and Vitzthumia Thor, 1930, and between the seven forms of Vitzthumia currently regarded as species. All instars of A. janus are voracious predators of nematodes and small arthropods. Development from egg to adult takes 9–11 days on a diet of rhabditid nematodes at 23 °C. Generation time for granular morph females is about 14 days. Females require insemination before eggs can be laid, and the sex ratio is about 1 male: 1.3 females.

Population dynamics of a thelastomatid nematode of cockroaches

Parasitology ◽  
1988 ◽  
Vol 96 (2) ◽  
pp. 353-368 ◽  
Author(s):  
S. Zervos
Keyword(s):  
Adult Female ◽  
Egg Production ◽  
Goodness Of Fit ◽  
Host Size ◽  
Infection Prevalence ◽  
Adult Males ◽  
Chi Square ◽  
Faecal Pellets ◽  
Adult Females ◽  
Juvenile Males

SummaryBlatticola monandros Zervos lives in the hind gut of the endemic New Zealand cockroach Parellipsidion pachycercum Johns. A field survey showed that infection prevalence was high (54 %) in small nymphs and increased further with cockroach size to a maximum (92 %) in penultimate nymphs. Variance to mean ratios and the Chi-square test for goodness of fit of a Poisson distribution provide strong evidence that the distribution of the nematode was not clumped (over-dispersed) or Poisson (random) but under-dispersed in most host size classes. The modal infrapopulation type consisted of 1 adult male and 1 adult female. Other infrapopulations were transitional to this type. Monogamous infrapopulations increased in prevalence with increased host size. Juvenile males were uncommon and probably develop faster into adults than juvenile females. Infrapopulations with 2 juvenile males were very rare and no cockroach contained 2 adult males, although some contained 2 adult females. Seasonal variations in prevalence and infrapopulation structure were slight over a 3 year period, except during one unusually dry summer. During the drought, prevalence of monogamous infrapopulations and of transitional infrapopulations were lowest, while prevalence of single-worm and single-sex infrapopulations were greatest. It is evident that competition between females reduces fecundity. When only 1 adult female nematode is present in an adult cockroach, more eggs are produced than the total produced if 2 adult females are present. Eggs were produced cyclically with short periods of high egg production interspersed with several days of very low or no egg production. Most eggs produced on any one day were attached to the outer surface of only 1 of the up-to-6 faecal pellets produced by the host/day. Mechanisms which may regulate infrapopulations and control reproductive competition and cyclical egg production are discussed. It is suggested that B. monandros regulates its own infrapopulation.

Spatial variability in the social organisation of the yellow-bellied glider (Petaurus australis) near Ravenshoe, north Queensland

2001 ◽  
Vol 49 (4) ◽  
pp. 397 ◽  
Author(s):  
Ross L. Goldingay ◽  
Darren G. Quin ◽  
Sue Churchill
Keyword(s):  
Adult Female ◽  
Social System ◽  
Dominant Male ◽  
Female Group ◽  
Sexually Dimorphic ◽  
Adult Males ◽  
Adult Females ◽  
The Social ◽  
Natal Home ◽  
Petaurus Australis

A detailed study was conducted over a 12-month period of 10 yellow-bellied glider groups at Nitchaga Creek in north Queensland. Adult gliders were sexually dimorphic in body size and were characterised by yellow ventral fur, which is consistent with southern populations. Gliders lived in groups of 3–6 individuals that occupied exclusive areas of about 50 ha. The structure of glider groups varied enormously: five contained one adult pair, three contained one adult male and 2–3 adult females, and two initially contained 2–3 adult males and one adult female but then persisted as bachelor groups after the death or disappearance of the adult female. Group size changed during the year as offspring matured and as individuals died. One male glider dispersed about 1 km from its natal home-range and became the dominant male in a nearby group. Young were born throughout the year, with a peak in the number of pouch-young in June. This study has confirmed the highly variable social system of the yellow-bellied glider, which appears to be mediated by local resource abundance.

Parasitism of the commercial sand crab Portunus pelagicus (L.) by the rhizocephalan Sacculina granifera Boschma, 1973 in Moreton Bay, Queensland, Australia

1994 ◽  
Vol 45 (2) ◽  
pp. 169 ◽  
Author(s):  
WD Sumpton ◽  
MA Potter ◽  
GS Smith
Keyword(s):  
Adult Female ◽  
Egg Mass ◽  
Size Distributions ◽  
Adult Males ◽  
Infection Rates ◽  
Portunus Pelagicus ◽  
Female Population ◽  
Moreton Bay ◽  
Adult Females

In Moreton Bay, Queensland, externae of Sacculina granifera Boschma were found in 7.0% of adult males and 123% of adult females of Portunus pelagicus. Infection rates were seasonal for both sexes and higher in the adult female population, with more than 20% of adult females carrying externae during some summer months. Infection rates were less than 3% in areas outside the bay and generally highest in the southern and central bay. Nineteen males and 15 females had abdominal scars where externae had become dislodged. The gonads of most parasitized crabs were underdeveloped, but 5.6% of externa-bearing females and 10% of externa-bearing males also had well developed gonads. Two female sand crabs were found with both a small egg mass and a mature externa (a condition not previously reported). Size distributions of infected and uninfected adult crabs were similar, suggesting that large crabs as well as juvenile crabs were likely to be infected.

scholarly journals Microhabitat preferences of the freshwater prawn Macrobrachium jelskii (Decapoda: Palaemonidae)

2019 ◽  
Vol 109 ◽  
Author(s):  
Jersei N. Silva ◽  
Guilherme de Oliveira ◽  
Sérgio S. da Rocha
Keyword(s):  
Sex Ratio ◽  
Water Reservoir ◽  
Habitat Choice ◽  
Freshwater Prawn ◽  
Adult Males ◽  
Adult Females ◽  
Males And Females ◽  
Microhabitat Preferences ◽  
Lower Depth ◽  
Juvenile Males

ABSTRACT We analyzed the microhabitat preferences of Macrobrachium jelskii (Miers, 1877) males and females inhabiting an urban water reservoir in Cruz das Almas, Bahia, Brazil. Prawns were collected monthly, from March 2015 to February 2016, in three microhabitats, using a sieve. Each microhabitat was dominated by one macrophyte species: Eleocharis sp. (M1), Cabomba sp. (M2), and Nymphaea sp. (M3). The prawns were measured (carapace length), and categorized as juvenile males, adult males, juvenile females, non-ovigerous adult females and ovigerous adult females. An analysis of variance (ANOVA) was used to compare the number and size of individuals. The sex ratio and frequency of ovigerous females in the three microhabitats were also calculated. The sex ratio was biased towards females in M1 and did not deviate from 1:1 in M2 and M3. When prawns were separated into five categories we observed that non-ovigerous adult females were more abundant in M1, while adult males were the most abundant demographic category in M2 and M3. Juveniles of both sexes and ovigerous females showed no microhabitat preference, although M1 and M2 appeared to be more suitable for the latter. Adult females were the largest individuals in all microhabitats. Food availability, lower depth and lower predation pressure in M1 are the main factors that make M1 more suitable for M. jelskii, particularly non-ovigerous adult females and larger adult males. Intraspecific competition for shelter in M1 might also occur and adult females win this competition due to their larger body size. Therefore, adult males are found in higher abundance in M2 and M3 and the juvenile of both sexes spread evenly across all microhabitats. Our results help to understand the ecological role and the niche used by M. jelskii. Future studies on the habitat choice and predation under laboratory conditions should help to understand the behavior of this species.

Blackbuck Antilope cervicapra (Mammalia: Cetartiodactyla: Bovidae) estimates in human-dominated landscape in Aligarh, Uttar Pradesh, India

2021 ◽  
Vol 13 (9) ◽  
pp. 19232-19238
Author(s):  
Mujahid Ahamad ◽  
Jamal A. Khan ◽  
Satish Kumar
Keyword(s):  
Sex Ratio ◽  
Uttar Pradesh ◽  
Adult Males ◽  
Forest Patches ◽  
Female Ratio ◽  
Adult Females ◽  
Or Groups ◽  
Feral Dogs ◽  
The Status ◽  
Antilope Cervicapra

Information on the status of the Indian Blackbuck Antilope cervicapra is mostly available from protected areas (PA), although 80% of its population occurs outside PAs. We conducted surveys to assess the status, age structure, sex ratio, and conservation issues of Blackbuck in and around Aligarh between February and June 2014. A median of 672 individuals at 18 separate locations were recorded with a group size ranging 4–216 except for solitary individuals. The abundance of Blackbuck was maximum in Sikandra Rao (range: 154–216) followed by Andla (range: 47–65), and Pala-Sallu (range: 53–62). Sex ratio was skewed towards females (1:4.5) with yearling to female and fawn to female ratio of 7.8:100 and 6.7:100, respectively. The percentage of adult males of Blackbuck (12.8% adult males, 8.4% sub-adult males) as well as adult females (56.4% adult females, 11.9% sub-adult females) was higher than other age classes or groups in the population. The preliminary observations indicate that the increasing population of free-ranging feral dogs, degradation of forest patches, social forestry plantations, competition with livestock, and poaching pressure are the major conservation issues of Blackbuck in the area. The current information is expected to serve as baseline in assessing the population of Blackbuck in the future. 

Life history, trophic behavior, and description of Gamasellodes vermivorax n. sp. (Mesostigmata: Ascidae), a predator of nematodes and arthropods in semiarid grassland soils

1987 ◽  
Vol 65 (7) ◽  
pp. 1689-1695 ◽  
Author(s):  
David Evans Walter
Keyword(s):  
Life History ◽  
Sex Determination ◽  
Adult Female ◽  
Generation Time ◽  
Life Stages ◽  
Adult Males ◽  
Microcosm Experiment ◽  
Grassland Soils ◽  
Semiarid Grassland ◽  
Determination Mechanism

All life stages of Gamasellodes vermivorax n. sp. (Mesostigmata: Ascidae), a predator of mites, collembolans, and nematodes in semiarid grassland soils, are described. Female to female generation time is 10 days on a diet of rhabditid nematodes at 24 °C. Each adult female may produce one to three eggs daily for at least 2 weeks. Female deutonymphs are guarded by adult males. Isolated female deutonymphs molt to adults which begin laying eggs within 48 h of emergence. All eggs laid by unfertilized females develop into males, indicating a haplodiploid sex determination mechanism. In a microcosm experiment, nematode densities were negatively correlated with G. vermivorax densities.

Changes in the Relationships of Captive Rhesus Monkeys On Giving Birth

Behaviour ◽  
1977 ◽  
Vol 61 (3-4) ◽  
pp. 304-321 ◽  
Author(s):  
R.A. Hinde ◽  
Linda Powell Proctor
Keyword(s):  
Adult Female ◽  
Rhesus Monkeys ◽  
The Other ◽  
Adult Males ◽  
Agonistic Interactions ◽  
Adult Females ◽  
Female Rhesus ◽  
The Times ◽  
Relative Preferences ◽  
Unrelated Adult

AbstractI) Relationships between captive adult female rhesus monkeys were assessed for 6 weeks before and 20 weeks after birth in terms of proximity, approaches and leavings, grooming and agonistic interactions. 2) Before the births, the mothers-to-be spent more time with (and more time grooming with) related than with unrelated individuals. Responsibility for proximity with unrelated adult females to whom the mother was dominant lay primarily with the mother, but where the other female was subordinate it might lie with either party. Mothers-to-be tended to groom adult females dominant to themselves more than they were groomed by them, and vice versa. 3) Differences between the times that mothers-to-be spent near members of different age/sex/rank classes could not be accounted for in terms of generalizations describing preferences of the mothers for members of those classes nor relative preferences of them for her. 4) After the births, members of all age/sex/rank classes tended to be near (and to groom) mothers more when the infants were on the mothers than when they were off but near her, and to be near the mother more when the infants were off but near than when the infants were off and distant from the mother. Proximity between mother and others tended to become more independent of the position of the baby as it developed. 5) Differences between age/sex/rank classes in time spent near the mother after birth were generally similar to those found before birth. The index for the mother's role in maintaining proximity was predominantly negative. 6) All age/sex/rank categories tended to be near the mother less after the birth than before, especially when the infant was off its mother. The differences disappeared with time. Adult males tended to groom the mother less, and adult females to groom her more, than before birth. 7) Changes in proximity between mother and other from before to after birth can be understood in terms of an increase in the attraction of others to mother and a decrease in mothers' affinity for others.

scholarly journals Study on the Prevalence of Ectoparasitic Arthropods on Free Range Gallus domesticus in Two Communities in Awka

2019 ◽  
pp. 1-7
Author(s):  
C. C. Nwadike ◽  
P. C. O. Ilozumba ◽  
C. J. Gaius
Keyword(s):  
Domestic Fowl ◽  
Gallus Domesticus ◽  
Adult Males ◽  
Male Adult ◽  
Adult Chicken ◽  
Argas Persicus ◽  
Free Range ◽  
Adult Females ◽  
Significant Difference ◽  
The Impact

A survey was carried out to determine the prevalence of ectoparasitic arthropods in free range domestic fowl (Gallus domesticus) in Amansea and Ifite communities, in Awka Capital Territory, Anambra state. A total of 112 G. domesticus comprising of 42 Adult males, 30 adult females and 40 juveniles were examined during a house to house survey for ectoparasitic arthropods. The study was carried out between June and September, 2014. The domestic fowl were caught in their roosting places at night and were examined for ectoparasitic arthropod infestation. 73.21% prevalence of ectoparasitic arthropods on the chicken was recorded. Male adult chicken had higher prevalence of ectoparasitic arthropods than adult females and juvenile chicken. Six species of ectoparasitic arthropods namely; Argas persicus (29.46%), Menopon gallinae (23.21%), Dermanysus gallinae (16.07%), Lipeurus caponis (12.5%), Echidnophaga gallinacea (10.71%) Goniocotes gallinae (5.36%) were recovered from infested chicken. Argas persicus with the prevalence (29.46%) was the most prevalent parasite species. Amansea community had a higher prevalence of ectoparasitic arthropods than Ifite community. The difference was statistically significant (P<0.05). In conclusion, the present study has provided information on the various ectoparasitic arthropods of domestic chicken in Amansea and Ifite communities. There was no significant difference in the prevalence of ectoparasitic arthropods between the two communities. Therefore, further study is needed to determine the impact of infestation on the health and productivity of these birds, and evaluation of cost benefit of various control strategies need to be investigated.

Masculinized females in a population of Leptodiaptomus minutus (Copepoda, Calanoida)

1998 ◽  
Vol 76 (3) ◽  
pp. 596-600 ◽  
Author(s):  
Kristine B Sillett ◽  
Richard S Stemberger
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Adult Males ◽  
Secondary Sexual Characteristics ◽  
Adult Females ◽  
Internal Morphology ◽  
Sexual Characteristics ◽  
The Common ◽  
Normal Males ◽  
Normal Adults

In a population of the common freshwater copepod Leptodiaptomus minutus Lilljeborg, 7.3% of adult females exhibited male secondary sexual characteristics. Although these masculinized or intersex females had the internal morphology of normal females, they possessed one or rarely two normal geniculate male antennules, and in a few instances male fifth legs. The sex ratio of normal adult males to females in the population was 1:1. No differences in body size among normal males, normal females, and masculinized females were found. Antennule lengths of males and masculinized females were not significantly different from one another; however, normal females had longer antennules than either males or masculinized females. Mating experiments indicated that masculinized females were functionally female and they were able to mate with normal males to produce offspring that were normal or masculinized. The occurrence of intersex copepods in lakes of North America may be more widespread than we now recognize because they can be easily overlooked or mistaken for normal adults.

On the mating system of polar bears

1986 ◽  
Vol 64 (10) ◽  
pp. 2142-2151 ◽  
Author(s):  
Malcolm A. Ramsay ◽  
Ian Stirling
Keyword(s):  
Sex Ratio ◽  
Sea Ice ◽  
Mating System ◽  
Breeding Season ◽  
Large Body ◽  
Arctic Sea Ice ◽  
Polar Bears ◽  
Adult Males ◽  
Terrestrial Mammals ◽  
Adult Females

Polar bears are intimately associated with arctic sea ice and their distribution is approximated by its winter extent. They are the only terrestrial mammals, other than humans, to have adapted so completely to sea ice, a quite different habitat, spatially and temporally, from that occupied by other terrestrial mammals. We propose that the dynamics of sea ice and the associated variability in access to food have played a major role in the evolution of the social structure and mating system of polar bears. Adult females and males move to areas of the sea ice where the greatest success in hunting is realized. Such regions are unpredictable in location, however, both seasonally and annually. Because female distributions are unpredictable, adult males are unable to defend stable territories that will encompass the home ranges of one or more females and may instead distribute themselves among different sea-ice habitats at the same relative densities as solitary adult females. Females keep nursing cubs with them for more than 1 year; hence the mean interbirth interval is 2 or more years. This results in a functionally skewed sex ratio, with fewer females available to breed in any one year than males, and in intrasexual competition among males for access to breeding females. Consequently, established dominance hierarchies among males are unstable, and wounding, scarring, and breakage of canine teeth are common; these are evidence of direct physical confrontations during the breeding season. Large body size is advantageous in these fights and this has resulted in one of the highest degrees of sexual dimorphism among terrestrial mammals. Because of the funtionally skewed sex ratio and the shifting distribution of both females and males, however, even the largest male probably cannot be certain of locating a larger than average number of receptive females in any one breeding season.

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