INVESTIGADORES
LARESCHI Marcela
artículos
Título:
Fecundity of Hoplopleura scapteromydis (Phthiraptera, Hoplopleuridae) ectoparasite of Scapteromys aquaticus (Rodentia: Muridae) in Rio de la Plata marshland, Argentina.
Autor/es:
LILJESTHROM GERARDO; MARCELA LARESCHI
Revista:
JOURNAL OF PARASITOLOGY
Referencias:
Año: 2001 vol. 87 p. 542 - 544
ISSN:
0022-3395
Resumen:
ABSTRACT: Density and age structure of lice collected from captured Scapteromys aquaticus rodents were studied to estimate
the fecundity of Hoplopleura scapteromydis. The number of eggs with a visible embryo inside (E), nymphs (N), adult males
(AM), and adult females (AF) were recorded for each rodent. For the ith rodent, the fecundity of H. scapteromydis, F(i), was
estimated as F(i) 5 {[E(i) 1 N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily
considered as T 5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.: Density and age structure of lice collected from captured Scapteromys aquaticus rodents were studied to estimate
the fecundity of Hoplopleura scapteromydis. The number of eggs with a visible embryo inside (E), nymphs (N), adult males
(AM), and adult females (AF) were recorded for each rodent. For the ith rodent, the fecundity of H. scapteromydis, F(i), was
estimated as F(i) 5 {[E(i) 1 N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily
considered as T 5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.Hoplopleura scapteromydis. The number of eggs with a visible embryo inside (E), nymphs (N), adult males
(AM), and adult females (AF) were recorded for each rodent. For the ith rodent, the fecundity of H. scapteromydis, F(i), was
estimated as F(i) 5 {[E(i) 1 N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily
considered as T 5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.H. scapteromydis, F(i), was
estimated as F(i) 5 {[E(i) 1 N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily
considered as T 5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.5 {[E(i) 1 N(i)]/2}/AF(i)/T, where T represents the period of preimaginal development (unknown and arbitrarily
considered as T 5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.5 1), and the sex ratio of the preimaginal stages was supposed to be 1:1. In order to look for density-dependent
effects, F(i) was plotted against AM(i), this being an independent estimation of infrapopulation density. The number of rodents
suitable for AF and AM calculations was 38 (57% of the parasitized animals). Almost 95% had a low-to-moderate louse burden
(1 , AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0., AM , 30) and were captured every season, whereas only 3% had a heavy (61 , AM , 70, captured in winter) or very
heavy (AM . 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.. 80, captured in summer) louse burden. The extreme values of F were 0.63 and 18 (1.3 and 36 if both sexes were
considered). High-to-moderate F-values (F . 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.. 5) were estimated in only 5 rodents that exhibited low louse density, whereas low
F-values (F , 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0., 5) were found at all louse densities. Notwithstanding the tendency toward an inverse relationship between fecundity
and infrapopulation density, the correlation was not significantly different from 0.