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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Reproductive Behavior and Population Ecology of Philus antennatus

Chiu, Chien-chih 01 September 2006 (has links)
Wendan Citrus grandis was introduced from FuJian province to Taiwan in 1701 (Kanghsi 40 years, Ching dynasty), and wide planted around Madou county, Tainan since. In recent years, it was found that Wendan was easily infected and damaged by long-horn beetle Philus antennatus, which caused damage even worse than another destructive insect, white-spotted Long-horned beetle Anoplophoa malasiaca. From May 2003 to May 2009, I investigated the reproduction, development and population dynamics of the beetle in a shaddock orchard in Madou, and conducted experiments on its behavior. The results showed that wrinkled triple like T character in the front chest and pronotum is one of the characteristics of Philus antennatus larva. The adults were nocturnal and often came out of the excavation in the night to copulate. After copulation, female would lay eggs in a small crack. After hatched, the larvae drilled into soil and dwelled in the host plant, eating wendan¡¦s fibrous roots, the phloem of the major roots, etc. Tender fibrous roots of shaddock¡¦s trunk were severely damaged by the larvae, resulting in host plants not able to transport water and nutrients to the leaves, which would dry out and drop. Consequently, the host plants would gradually die. The life cycle of Philus antennatus lasted about one to two years. Four stages, egg, larva, pupa and adult were observed to complete metamorphosis. The adult¡¦s life is short. After eclosion, the adults hide in the soil and do not eat. They will come out of the excavation only for copulation, and then died about 5 days after copulation. Eclosion stage lasts about 30 days, starting in late May, and incubation of egg takes about 13 -18 days. The larva stage lasts 1-2 years. But with bad climate or unfavorable environment, ecdysis would extend, and larvae would not eclosion
2

Population dynamics and assessment of exploited deep water decapods of Balearic Islands (western Mediterranean): from single to multi-species approach

Guijarro González, Beatriz 03 October 2012 (has links)
In the western Mediterranean, deep water decapod crustaceans form a considerable fraction of the megafaunal biomass in the upper and middle slope, being a very important component of the catches of the commercial fishery. The main objective of this thesis is to analyse the community and population dynamics of the deep water decapod crustaceans off the Balearic Islands. Data have been obtained from scientific surveys, from the fishing sector and from selectivity pilot studies. Univariate and multivariate techniques have been used to analyse the data. The knowledge derived from this thesis provide relevant information about how the species traits are mainly affected by water masses, sediment characteristic, trophic resources and fishing, since they influence the bathymetric distribution, abundances, biological parameters and condition of decapod crustaceans at a local scale. This knowledge is a key point for a better assessment of the resources and for a better application of the Ecosystem-Based Approach Management in the Mediterranean deep water ecosystems

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