Photoperiodic, thermal and trophic responses of a predatory ladybird Cheilomenes propinqua

2020 ◽  
Author(s):  
Sergey Reznik ◽  
Andrey Ovchinnikov ◽  
Antonina Ovchinnikova ◽  
Olga Bezman‐Moseyko ◽  
Natalia Belyakova
Keyword(s):  
Trophic Responses

scholarly journals Anterior pituitary trophic responses to dexamethasone withdrawal and repeated dexamethasone exposures

2001 ◽  
Vol 169 (2) ◽  
pp. 263-270 ◽  
Author(s):  
LA Nolan ◽  
A Levy
Keyword(s):  
Hpa Axis ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Duration Of Treatment ◽  
Glucocorticoid Treatment ◽  
Initial Exposure ◽  
Male Wistar Rats ◽  
Anatomic Basis ◽  
Delayed Recovery ◽  
Trophic Responses

Glucocorticoid withdrawal, depending on the dose and duration of treatment, results in a transient but sometimes prolonged reduction in hypothalamo-pituitary-adrenal (HPA) axis secretory responsiveness. As the anatomic basis of HPA axis suppression remains uncertain, we have directly examined changes in trophic activity within the rat anterior pituitary gland following dexamethasone withdrawal and re-treatment. Treatment of adrenalectomised, male Wistar rats with dexamethasone results in a discrete, highly significant burst of apoptosis in the anterior pituitary with concurrent suppression of mitosis. Despite a surge in mitotic activity immediately after dexamethasone withdrawal, calculated total anterior pituitary cell populations remain below that seen in untreated adrenalectomised controls. Repeated exposures to dexamethasone show that the dexamethasone-sensitive cell population that is deleted by apoptosis is partially but not completely restored. As the amplitude of apoptotic bursts induced by second and third dexamethasone exposures are similar but smaller than that induced by initial exposure, it appears that the very first exposure to dexamethasone deletes a subset of anterior pituitary cells that are either not restored at all, or are only replaced very slowly. The reduced proportion of corticotrophs contributing to the increase in mitotic index after dexamethasone withdrawal corroborates this. Although continued cell turnover within the pituitary predicts that the absolute cellular deficit would diminish with time, the effects seen may contribute to the delayed recovery of pituitary axis function following cessation of glucocorticoid treatment.

Fish assemblage-environment relationships suggest differential trophic responses to heavy metal contamination

2019 ◽  
Vol 64 (4) ◽  
pp. 632-642 ◽  
Author(s):  
Kevin P. Krause ◽  
Chin-Lung Wu ◽  
Maria L. Chu ◽  
Jason H. Knouft
Keyword(s):  
Heavy Metal ◽  
Fish Assemblage ◽  
Metal Contamination ◽  
Heavy Metal Contamination ◽  
Trophic Responses

scholarly journals Decoupled trophic responses to long‐term recovery from acidification and associated browning in lakes

2019 ◽  
Vol 25 (5) ◽  
pp. 1779-1792 ◽  
Author(s):  
Taylor H. Leach ◽  
Luke A. Winslow ◽  
Nicole M. Hayes ◽  
Kevin C. Rose
Keyword(s):  
Recovery From Acidification ◽  
Trophic Responses

Trophic responses to trauma in growing antlers

1965 ◽  
Vol 159 (3) ◽  
pp. 289-302 ◽  
Author(s):  
Anthony B. Bubenik ◽  
R. Pavlansky
Keyword(s):  
Trophic Responses

Divergent trophic responses to biogeographic and environmental gradients

Oikos ◽  
2016 ◽  
Vol 126 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Miguel G. Matias ◽  
Cátia Lúcio Pereira ◽  
Pedro Miguel Raposeiro ◽  
Vítor Gonçalves ◽  
Ana Mafalda Cruz ◽  
...  
Keyword(s):  
Environmental Gradients ◽  
Trophic Responses

scholarly journals Trophic responses to nutrient enrichment in a temperate seagrass food chain

2012 ◽  
Vol 449 ◽  
pp. 291-296 ◽  
Author(s):  
PH York ◽  
BP Kelaher ◽  
DJ Booth ◽  
MJ Bishop
Keyword(s):  
Food Chain ◽  
Nutrient Enrichment ◽  
Trophic Responses

scholarly journals Humans disrupt access to prey for large African carnivores

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kirby L Mills ◽  
Nyeema C Harris
Keyword(s):  
Prey Species ◽  
Prey Selection ◽  
Diel Activity ◽  
Spotted Hyena ◽  
Nocturnal Activity ◽  
Ecological Processes ◽  
Predator Prey ◽  
Human Presence ◽  
Prey Resources ◽  
Trophic Responses

Wildlife respond to human presence by adjusting their temporal niche, possibly modifying encounter rates among species and trophic dynamics that structure communities. We assessed wildlife diel activity responses to human presence and consequential changes in predator-prey overlap using 11,111 detections of 3 large carnivores and 11 ungulates across 21,430 camera trap-nights in West Africa. Over two-thirds of species exhibited diel responses to mainly diurnal human presence, with ungulate nocturnal activity increasing by 7.1%. Rather than traditional pairwise predator-prey diel comparisons, we considered spatiotemporally explicit predator access to several prey resources to evaluate community-level trophic responses to human presence. Although leopard prey access was not affected by humans, lion and spotted hyena access to three prey species significantly increased when prey increased their nocturnal activity to avoid humans. Human presence considerably influenced the composition of available prey, with implications for prey selection, demonstrating how humans perturb ecological processes via behavioral modifications.

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