ABSTRACT
In the Azores archipelago, a significant proportion of buildings are infested with the urban exotic drywood termite Cryptotermes brevis (Walker), causing major economical and patrimonial losses. This work aims to understand the potential spread of this termite species in the Azores and estimate the costs for both treatment and reconstruction of infested buildings in the entire archipelago. A maximum entropy niche modeling process was used to determine the potential occurrence of the species on each island. Different scenarios were built using independent global and regional incidence and environmental data. Both projections reveal the same pattern. Generally, the probability of occurrence is higher near the coast line, where, in Azores, the majority of the towns and villages are located. We also predict that the infestation has potential to spread to yet unaffected towns and islands. It is estimated that the cost of treating all currently infested buildings in the archipelago is Euro 51 million, while reconstruction of the same buildings would rise the costs to Euro 175 million. We predict that the absence of a control strategy will cause a further expansion of the pest to more localities in the Azores. An estimate to future scenarios implies higher costs, with treatment and rebuilding values rising up to eight times the current values.
Subject(s)
Isoptera , Animals , Azores , Climate , Costs and Cost Analysis , Geography , Models, TheoreticalABSTRACT
The termite Cryptotermes brevis (Walker) (Isoptera: Kalotermitidae) is an urban pest that causes much damage to wood structures. Little has been done concerning the use of control methods for alates. C. brevis is known to have phototropic behavior during the dispersal flights, and this knowledge has been applied for preventative control in the Azores where this species is a serious urban pest. We were interested in determining whether there was a light wavelength preference by the alates of C. brevis to optimize light traps against this species. Six light wavelengths were tested: 395 nm (UV), 460-555 nm (white), 470 nm (blue), 525 nm (green), 590 nm (yellow), and 625 nm (red) in choice chambers, with dark chambers as controls. Two populations were tested, one population in Florida and one population in the Azores (Terceira Island). We found consistent results for both populations, with a preference for the light wavelengths in the white, blue, and green spectrum (460-550 nm). This information can be used to build more effective light traps that can be used by home owners in the Azores to help control this pest.
Subject(s)
Behavior, Animal/radiation effects , Isoptera/radiation effects , Animals , Azores , Color , Florida , Insect Control , LightABSTRACT
The arthropod species richness of pastures in three Azorean islands was used to examine the relationship between local and regional species richness over two years. Two groups of arthropods, spiders and sucking insects, representing two functionally different but common groups of pasture invertebrates were investigated. The local-regional species richness relationship was assessed over relatively fine scales: quadrats (= local scale) and within pastures (= regional scale). Mean plot species richness was used as a measure of local species richness (= alpha diversity) and regional species richness was estimated at the pasture level (= gamma diversity) with the 'first-order-Jackknife' estimator. Three related issues were addressed: (i). the role of estimated regional species richness and variables operating at the local scale (vegetation structure and diversity) in determining local species richness; (ii). quantification of the relative contributions of alpha and beta diversity to regional diversity using additive partitioning; and (iii). the occurrence of consistent patterns in different years by analysing independently between-year data. Species assemblages of spiders were saturated at the local scale (similar local species richness and increasing beta-diversity in richer regions) and were more dependent on vegetational structure than regional species richness. Sucking insect herbivores, by contrast, exhibited a linear relationship between local and regional species richness, consistent with the proportional sampling model. The patterns were consistent between years. These results imply that for spiders local processes are important, with assemblages in a particular patch being constrained by habitat structure. In contrast, for sucking insects, local processes may be insignificant in structuring communities.