scholarly journals Calanoid Copepods: An Overlooked Tool in the Control of Disease Vector Mosquitoes

2018 ◽  
Vol 55 (6) ◽  
pp. 1656-1658 ◽  
Author(s):  
Ross N Cuthbert ◽  
Tatenda Dalu ◽  
Ryan J Wasserman ◽  
Amanda Callaghan ◽  
Olaf L F Weyl ◽  
...  
2020 ◽  
Vol 57 (6) ◽  
pp. 1983-1987
Author(s):  
Ross N Cuthbert ◽  
Tatenda Dalu ◽  
Ryan J Wasserman ◽  
Olaf L F Weyl ◽  
P William Froneman ◽  
...  

Abstract Predation is a critical factor that mediates population stability, community structure, and ecosystem function. Predatory natural enemies can contribute to the regulation of disease vector groups such as mosquitoes, particularly where they naturally co-occur across landscapes. However, we must understand inter-population variation in predatory efficiency if we are to enhance vector control. The present study thus employs a functional response (FR; resource use under different densities) approach to quantify and compare predatory interaction strengths among six populations of a predatory temporary pond specialist copepod, Lovenula raynerae, from the Eastern Cape of South Africa preying on second instar Culex pipiens complex mosquito larvae. All individuals from the sampled populations were predatory and drove significant mortality through per capita predation rates of 0.75–1.10 mosquitoes/h at maximum densities over a 5-h feeding time. Individuals from all copepod populations exhibited Type II FRs with no significant differences in attack rates. On the other hand, there were significant differences in handling times, and therefore also maximum feeding rates (maximum experimental prey density: 32), suggesting possible genetic differences among populations that influenced predation. Owing to a widespread distribution in arid landscapes, we propose that predatory calanoid copepods such as L. raynerae play a key regulatory role at the landscape scale in the control of disease vector mosquito populations. We propose that these ecosystems and their specialist biota should thus be conserved and enhanced (e.g., via selective breeding) owing to the ecosystem services they provide in the context of public health.


Author(s):  
T. M. Weatherby ◽  
P.H. Lenz

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.


2020 ◽  
Vol 643 ◽  
pp. 197-217 ◽  
Author(s):  
SME Fortune ◽  
SH Ferguson ◽  
AW Trites ◽  
B LeBlanc ◽  
V LeMay ◽  
...  

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada-West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.


2020 ◽  
Vol 55 (1) ◽  
pp. 478-487
Author(s):  
Abinash Bhattachan ◽  
Nicholas K. Skaff ◽  
Amanda M. Irish ◽  
Solomon Vimal ◽  
Justin V. Remais ◽  
...  

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elise Skottene ◽  
Ann M. Tarrant ◽  
Anders J. Olsen ◽  
Dag Altin ◽  
Mari-Ann Østensen ◽  
...  

Abstract Calanus copepods are keystone species in marine ecosystems, mainly due to their high lipid content, which is a nutritious food source for e.g. juvenile fish. Accumulated lipids are catabolized to meet energy requirements during dormancy (diapause), which occurs during the last copepodite stage (C5). The current knowledge of lipid degradation pathways during diapause termination is limited. We characterized changes in lipid fullness and generated transcriptional profiles in C5s during termination of diapause and progression towards adulthood. Lipid fullness of C5s declined linearly during developmental progression, but more β-oxidation genes were upregulated in early C5s compared to late C5s and adults. We identified four possible master regulators of energy metabolism, which all were generally upregulated in early C5s, compared to late C5s and adults. We discovered that one of two enzymes in the carnitine shuttle is absent from the calanoid copepod lineage. Based on the geographical location of the sampling site, the field-samples were initially presumed to consist of C. finmarchicus. However, the identification of C. glacialis in some samples underlines the need for performing molecular analyses to reliably identify Calanus species. Our findings contributes to a better understanding of molecular events occurring during diapause and diapause termination in calanoid copepods.


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