Trophic relations between adult water beetles from the Dytiscidae family and non-biting midges (Diptera: Chironomidae)

Biologia ◽  
2016 ◽  
Vol 71 (8) ◽  
Author(s):  
Anna Frelik ◽  
Jacek Koszałka ◽  
Joanna Pakulnicka

AbstractPredation is an exceptionally important interaction observed in the natural environment. It regulates the population size of potential prey and at the same time decreases competitiveness between them. Among predators inhabiting water environments, especially notable predators are water beetles, particularly adults of Dytiscidae. The results presented herein are an attempt to learn the trophic relations between adult Dytiscidae and non-biting midges (Diptera: Chironomidae). The studies were conducted in one-month intervals from April to September 2012–2013. In the diet structure of adult Dytiscidae of two size categories, the genus

2010 ◽  
Vol 67 (9) ◽  
pp. 1449-1458 ◽  
Author(s):  
Donald M. Van Doornik ◽  
Barry A. Berejikian ◽  
Lance A. Campbell ◽  
Eric C. Volk

Conservation hatcheries, which supplement natural populations by removing adults or embryos from the natural environment and rearing and releasing parr, smolts, or adults back into their natal or ancestral streams, are increasingly being used to avoid extinction of localized populations of Pacific salmonids. We collected data before and during a steelhead ( Oncorhynchus mykiss ) supplementation program to investigate the effect that the program has had on the population’s genetic diversity and effective population size and any changes to an important life history trait (residency or anadromy). We found that supplementation did not cause substantial changes in the genetic diversity or effective size of the population, most likely because a large proportion of all of the steelhead redds in the river each year were sampled to create the supplementation broodstock. Our data also showed that the captively reared fish released as adults successfully produced parr. Furthermore, we found that during supplementation, there was an increase in the proportion of O. mykiss with anadromous ancestry vs. resident ancestry.


2007 ◽  
Vol 34 (8) ◽  
pp. 632 ◽  
Author(s):  
Darren Bos ◽  
Susan M. Carthew

We know little about the availability of potential prey and patterns of prey consumption by Ningaui yvonneae in a natural environment. This information is important to understanding how the species is able to exploit its semiarid environment. Here, we examine the diet of N. yvonneae inhabiting a semiarid mallee community in South Australia using a combination of faecal analysis and observations of nocturnally foraging animals. Prey consumption was compared with the availability of prey types in the environment, and comparisons made between habitat components, across seasons and between sexes. N. yvonneae was found to include a range of prey types in its diet, with 11 invertebrate taxa recorded from direct observation and eight of these detected in the scats. Prey taxa consumed most often by freely foraging ningauis were Araneae, Blattodea and Orthoptera, while those most commonly detected in scats were Hymenoptera and Araneae. In comparison, 22 invertebrate taxa were recorded in pitfall traps, although many of these were recorded infrequently. Taxa most commonly recorded in traps were Hymenoptera, Collembola, Coleoptera and Acariformes. Observational data also indicated that consumption of prey taxa differed significantly between sexes and among seasons. Males generally consumed a more diverse array of prey, with both observational and scat data showing that they were more likely to consume Hymenoptera and Isoptera, while females were more likely to consume Lepidoptera and Hemiptera. Variability between seasons was evident in consumption of invertebrate grubs (recorded only during ‘growth’; February–April), Orthoptera (recorded most often during ‘breeding’, August–October), and Araneae (recorded more often during ‘maturation’, May–July). However percentage occurrence data from the scats lacked this seasonality, possibly because of the smaller array of prey taxa recorded. N. yvonneae captured prey from all available habitat components, with five of the most frequently recorded prey taxa being recorded from all components. Leaf litter and Triodia were the most commonly recorded capture sites (45% and 22% of captures respectively), and males and females used the habitat components in a similar manner. Although N. yvonneae is like many other dasyurids in having a largely generalist insectivorous diet, comparisons of prey consumed with their availability in the environment indicated that individuals did show some selectivity towards certain taxa, particularly Blattodea, Orthoptera, Chilopoda, Lepidoptera and Araneae.


2019 ◽  
Vol 30 (1) ◽  
pp. 1-6
Author(s):  
Wojciech Gotkiewicz ◽  
Krzysztof Wittbrodt

Abstract The paper presents the results of a 5-year study on the population size of the white stork (Ciconia ciconia L.) as one of the indicator species used to assess a biodiversity level in agricultural areas. The study was carried out in Masurian Landscape Park situated in Warmińsko-Mazurskie Voivodeship. The results demonstrated that the white stork population size was closely linked to agricultural areas, in particular, the extensively managed permanent grassland. In the years 2014–2018, even if minor changes were observed in the land use structure, the white stork population size showed a slight upward trend within the study area. In order to maintain this status, efforts should be made to preserve open landscapes (first and foremost – meadows and pastures), which are preferred feeding grounds of white stork. Consequently, potential decision as regards afforestation and housing should be made considerately.


2019 ◽  
Vol 42 ◽  
Author(s):  
Laurel Symes ◽  
Thalia Wheatley

AbstractAnselme & Güntürkün generate exciting new insights by integrating two disparate fields to explain why uncertain rewards produce strong motivational effects. Their conclusions are developed in a framework that assumes a random distribution of resources, uncommon in the natural environment. We argue that, by considering a realistically clumped spatiotemporal distribution of resources, their conclusions will be stronger and more complete.


2018 ◽  
Vol 41 ◽  
Author(s):  
Daniel Crimston ◽  
Matthew J. Hornsey

AbstractAs a general theory of extreme self-sacrifice, Whitehouse's article misses one relevant dimension: people's willingness to fight and die in support of entities not bound by biological markers or ancestral kinship (allyship). We discuss research on moral expansiveness, which highlights individuals’ capacity to self-sacrifice for targets that lie outside traditional in-group markers, including racial out-groups, animals, and the natural environment.


Author(s):  
Delbert E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
T. Fast ◽  
J. Stevenson ◽  
...  

Space Lab 3 (SL-3) was flown on Shuttle Challenger providing an opportunity to measure the effect of spaceflight on rat testes. Cannon developed the idea that organisms react to unfavorable conditions with highly integrated metabolic activities. Selye summarized the manifestations of physiological response to nonspecific stress and he pointed out that atrophy of the gonads always occurred. Many papers have been published showing the effects of social interaction, crowding, peck order and confinement. Flickinger showed delayed testicular development in subordinate roosters influenced by group numbers, social rank and social status. Christian reported increasing population size in mice resulted in adrenal hypertrophy, inhibition of reproductive maturation and loss of reproductive function in adults. Sex organ weights also declined. Two male dogs were flown on Cosmos 110 for 22 days. Fedorova reported an increase of 30 to 70% atypical spermatozoa consisting of tail curling and/or the absence of a tail.


Author(s):  
Robin Attfield ◽  
Andrew Belsey
Keyword(s):  

Author(s):  
Roy W. Pickens ◽  
Steven W. Gust ◽  
Philip M. Catchings ◽  
Dace S. Svikis
Keyword(s):  

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