Improving the assessment of predator functional responses by considering alternate prey and predator interactions

Ecology ◽  
2017 ◽  
Vol 98 (7) ◽  
pp. 1787-1796 ◽  
Author(s):  
K. Chan ◽  
S. Boutin ◽  
T. J. Hossie ◽  
C. J. Krebs ◽  
M. O'Donoghue ◽  
...  
2021 ◽  
Vol 168 (3) ◽  
Author(s):  
Ross N. Cuthbert ◽  
Ryan J. Wasserman ◽  
Tatenda Dalu ◽  
Elizabeta Briski

AbstractInvasive alien species impacts might be mediated by environmental factors such as climatic warming. For invasive predators, multiple predator interactions could also exacerbate or dampen ecological impacts. These effects may be especially pronounced in highly diverse coastal ecosystems that are prone to profound and rapid regime shifts. We examine emergent effects of warming on the strength of intraspecific multiple predator effects from a highly successful invasive gammarid Gammarus tigrinus, using a functional response approach towards larval chironomids (feeding rates under different prey densities). Single predator maximum feeding rates were three-times higher at 24 °C compared to 18 °C overall, with potentially prey destabilising type II functional responses exhibited. However, pairs of gammarids exhibited intraspecific multiple predator effects that were in turn mediated by temperature regime, whereby synergisms were found at the lower temperature (i.e. positive non-trophic interactions) and antagonisms detected at the higher temperature (i.e. negative non-trophic interactions) under high prey densities. Accordingly, warming scenarios may worsen the impact of this invasive alien species, yet implications of temperature change are dependent on predator–predator interactions. Emergent effects between abiotic and biotic factors should be considered in ecological impact predictions across habitat types for invasive alien species.


1991 ◽  
Vol 179 (1) ◽  
pp. 551-557 ◽  
Author(s):  
Grace G. Deanin ◽  
A.Marina Martinez ◽  
Janet R. Pfeiffer ◽  
Mary E. Gardner ◽  
Janet M. Oliver

2000 ◽  
Vol 279 (4) ◽  
pp. C1189-C1197 ◽  
Author(s):  
B. J. Gu ◽  
W. Y. Zhang ◽  
L. J. Bendall ◽  
I. P. Chessell ◽  
G. N. Buell ◽  
...  

Lymphocytes from normal subjects and patients with B-chronic lymphocytic leukemia (B-CLL) show functional responses to extracellular ATP characteristic of the P2X7receptor (previously termed P2Z). These responses include opening of a cation-selective channel/pore that allows entry of the fluorescent dye ethidium and activation of a membrane metalloprotease that sheds the adhesion molecule L-selectin. The surface expression of P2X7receptors was measured in normal leucocytes, platelets, and B-CLL lymphocytes and correlated with their functional responses. Monocytes showed four- to fivefold greater expression of P2X7than B, T, and NK lymphocytes, whereas P2X7expression on neutrophils and platelets was weak. All cell types demonstrated abundant intracellular expression of this receptor. All 12 subjects with B-CLL expressed lymphocyte P2X7at about the same level as B lymphocytes from normal subjects. P2X7function, measured by ATP-induced uptake of ethidium, correlated closely with surface expression of this receptor in normal and B-CLL lymphocytes and monocytes ( n = 47, r = 0.70; P< 0.0001). However, in three patients the ATP-induced uptake of ethidium into the malignant B lymphocytes was low or absent. The lack of P2X7function in these B lymphocytes was confirmed by the failure of ATP to induce Ba2+uptake into their lymphocytes. This lack of function of the P2X7receptor resulted in a failure of ATP-induced shedding of L-selectin, an adhesion molecule that directs the recirculation of lymphocytes from blood into the lymph node.


Author(s):  
Isabella Provera ◽  
Cristina Piñeiro-Corbeira ◽  
Rodolfo Barreiro ◽  
Laura Díaz-Acosta ◽  
Pilar Díaz-Tapia

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