178 research outputs found
Long-term impact of exotic ants on the native ants of Madeira
1. The earliest exotic records for two notorious invasive ants, the
big-headed ant ( Pheidole megacephala ) and the Argentine ant ( Linepithema humile ),
both come from the Atlantic islands of Madeira, where the two species underwent
population explosions in the 1850s and 1890s respectively. Researchers have long
assumed that these invaders spread across all of Madeira and exterminated most or all
native ants, despite no research actually documenting such impact.
2. Re-examination of first-hand nineteenth century accounts suggest that
P. megacephala and L. humile may never have spread beyond coastal lowland areas,
representing < 10% of Madeira’s land area. In 2002, native ants dominated most of
Madeira; P. megacephala and L. humile were restricted to ≈ 0.3% and ≈ 6% of
Madeira’s land area respectively.
3. Of the 10 native ant species known from Madeira, only one ( Temnothorax
wollastoni ) was not present in 1999 – 2002 surveys. Although exotic ants may have
exterminated T. wollastoni , it seems likely that this species still survives.
4. Thus, even after 150 or more years of residence, P. megacephala and L. humile
have come to occupy only a small part of Madeira, and appear to have had little impact.
5. Most of Madeira may be too cool for P. megacephala and perhaps too moist for
L. humile to dominate. Also, Madeira’s vast natural areas may generally lack weedy
vegetation that can support high densities of plant-feeding Hemiptera critical for the
ecological dominance of invasive ants. Finally, a dominant native ant, Lasius grandis ,
inhabiting ≈ 84% of Madeira, may actively exclude P. megacephala and L. humileinfo:eu-repo/semantics/publishedVersio
Nuclear localization of testosterone, dihydrotestosterone and estradiol-17β in basal rat brain
INTERACTIONS OF TESTOSTERONE AND ESTRADIOL WITH THE NEONATAL RAT BRAIN : PROTECTIVE MECHANISM AND POSSIBLE RELATIONSHIP TO SEXUAL DIFFERENTIATION
International audienc
Parameters of neuroendocrine aromatization and estrogen receptor occupation in the male rat
Characterization by high performance liquid chromatography of nuclear metabolites of testosterone in the brains of male rhesus monkeys
Identification of a stable fragment of the Alzheimer amyloid precursor containing the beta-protein in brain microvessels.
The action of 5α-dihydrotestosterone and antiandrogens on the activities of 5α-reductase and 3α-hydroxysteroid dehydrogenase in the pituitary gland of gonadectomized rats
Metabolic control of the behavioural action of androgens in the dove brain: Testosterone inactivation by 5β-reduction
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