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Previous issue date: 1997-12-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The first experiment was set up to measure the drop-off rhythm of larvae and nymphs of
Amblyomma cajennense feeding on the rabbits as experimental hosts. Infestations were
carried out with unfed larvae and nymphs aging 15 and 45 days post eclosion and host larval
moulting, respectively. Three rabbits were infested with approximately 825 larvae (50 mg of
eggs) and 100 nymphs for each age totaling 12 rabbits. Each host were examined at 8, 12, 16
and 24 hours and the dropped larvae and nymphs collected. Regardless of age and instar
higher drop-off rhythm were observed from 8 to 16 hours: 73,6 and 72,8% larvae with 15 and
45 days post eclosion and 69,6 and 57,5 nymphs with 15 and 45 days post larval moulting,
respectively. The second experiment was set up to evaluate the effect of age on the attachment
of larvae and nymphs of Amblyomma cajennense using the rabbit as experimental host.
Infestations were carried out with unfed larvae aging from 0-4 to 150 days post-eclosion and
unfed nymphs aging from 0-2 to 165 days post-larval moulting. A total of 11 and 12
infestations respectively for larvae and nymphs with 15 days interval were monitored. Three
rabbits were infested with 825 larvae and 100 nymphs per rabbit at each interval. Larvae and
nymphs with 0-2 day post-eclosion and post larval moulting were able to attach and feed at
rates of 45 and 77%. Higher attachment rates for larva (> 70%) were observed from days 15
to 60 post eclosion. Then, start to decrease until 25% at 150 days post-eclosion. Higher
attachment rates for nymphs were observed from days 15 to 90 post moulting (> 80%). Then,
start to decrease until 36% at 165 days. The periods of attachment and ecdisis, and the
percentage of ecdisis were similar for both stages regardless the age prior attachment. When
the period of pre-ecdisis is analyzed one might note a shortening as the nymphs because older
whereas it was similar for larvae in ali evaluated ages. This third experiment was conduct as
an attempt to correlate the weight pre-ecdisis period and timing of drop-off of nymphs with
the forecast of the sexes in adults of Rhipicephalus sanguineus. The mean weight of nymphs
that moulted to males (n = 96) was 1,97 ? 0,97 and 2,52 ? 0,90 to females (n = 103) (P >
0,05) between the weight of nymphs can not be used to forecast the sexes due to overlapping
of to weight ranges. The pre-ecdisis periods were 15,13 ? 0,94 and 14,60 ? 0,77 days for
nymphs that moulted to males (n = 96) and females (n = 103) (P > 0,05) respectively.
Nymphs (n = 50) that dropped-off on both third and fourth day (mode) post-infestation
moulted to 29 females and 21 males whereas those (n = 50) that dropped-off on the fifth day
post-infestation moulted to 30 females and 20 males (x2 > 0,05). Although there are numerical
differences in ali evaluated parameters none can be used to forecast the sexes in R. sanguineus
due to an extensive overlapping. / O primeiro experimento foi montado para avaliar o ritmo de queda de larvas e ninfas de
Amblyomma cajennense alimentadas em coelhos. Infesta??es foram feitas com larvas e ninfas
em jejum com idades de 15 e 45 dias ap?s eclos?o e ecdise larval respectivamente. Tr?s
coelhos foram infestados com aproximadamente 825 larvas (50 mg de ovos) e 100 ninfas para
cada idade totalizando 12 coelhos. Cada hospedeiro foi examinado nos hor?rios de 8, 12, 16 e
24 horas e as larvas e ninfas desprendidas foram coletadas. Independente da idade e do instar,
o maior n?mero se desprendeu entre 8 e 16 horas: 73,6% e 72,8% para larvas com 15 e 45
dias ap?s eclos?o e 69,6% e 57,5% para ninfa. Com 15 e 45 dias ap?s ecdise larval,
respectivamente. O segundo experimento teve como objetivo avaliar o efeito da idade sobre a
fixa??o de larvas e ninfas de Amblyomma cajennense, usando o coelho como hospedeiro.
Infesta??es foram feitas com larvas com per?odos de jejum de zero a 4 at? 150 dias ap?s
eclos?o e ninfas em jejum variando de zero a 2 at? 165 dias ap?s ecdise larval. Um total de 11
e 12 infesta??es para larvas e ninfas respectivamente, com intervalos de 15 dias foram
acompanhados. Tr?s coelhos foram infestados com 825 larvas e 100 ninfas por coelhos e para
cada tratamento. Larvas e ninfas com zero a 4 dias ap?s eclos?o e zero a 2 dias ap?s ecdise
larval se fixaram e se alimentaram, com taxas de recupera??o de 45 e 77% respectivamente.
Taxas de recupera??o alta para larvas (> 70%) foi observado para 15 at? 60 dias ap?s eclos?o.
Entretanto a partir da? come?ou a decrescer para 25% at? 150 dias p?s-eclos?o. As taxas de
recupera??o foram altas para ninfas com 15 at? 90 dias p?s-ecdise (> 80%). Ent?o, come?ou a
decrescer para 36% at? 165 dias. Os per?odos de pr?-ecdise, de ecdise e as percentagens de
ecdise foram est?veis para todas as idades estudadas. Quando o per?odo de pr?-ecdise ?
analisado nota-se um encurtamento conforme as ninfas se tornam mais velhas; ao contr?rio
este per?odo foi similar para larvas de todas as idades. Esse terceiro experimento foi
conduzido para se observar a correla??o entre o peso, o per?odo de pr?-ecdise e o per?odo de
queda de ninfas ingurgitadas com a previs?o do sexo dos adultos de Rhipicephalus
sanguineus. A m?dia do peso de ninfas que originaram machos (n = 96) foi de 1,97 ? 0,97 e
2,52 ? 0,90 para f?meas (n = 103) (P > 0,05). O peso das ninfas n?o pode ser usado para a
previs?o dos sexos devido ? superposi??o dos pesos. O per?odo de pr?-ecdise foi de 15,13 ?
0,94 e 14,60 ? 0,77 dias par ninfas que originaram machos (n = 96) e f?meas (n = 103) (P >
0,05), respectivamente. Ninfas (n = 50), dos per?odos de queda, inicial (3? dia) e modal (4?
dia), desprenderam-se 29 f?meas e 21 machos, em ambos per?odos. No per?odo final (5? dia)
(n = 50) desprenderam-se 30 f?meas e 20 machos (x2 > 0,05). Embora exista diferen?as
num?ricas em todos os par?metros avaliados, tais par?metros n?o podem ser utilizados para a
previs?o dos sexos em R. sanguineus devido a amplitude da superposi??o.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:tede/852 |
| Date | 16 December 1997 |
| Creators | Ribeiro, Armando de Lemos |
| Contributors | Faccini, Jo?o Luiz Horacio |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Curso de P?s-Gradua??o em Ci?ncias Veterin?rias, UFRRJ, Brasil, Parasitologia Veterin?ria |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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