Resource partitioning and overlap in three sympatric species of Ips bark beetles (Coleoptera: Scolytidae)

Oecologia ◽  
2001 ◽  
Vol 128 (3) ◽  
pp. 443-453 ◽  
Author(s):  
Bruce D. Ayres ◽  
Matthew P. Ayres ◽  
Mark D. Abrahamson ◽  
Stephen A. Teale
Zootaxa ◽  
2010 ◽  
Vol 2569 (1) ◽  
pp. 55 ◽  
Author(s):  
L. LEE GRISMER ◽  
CHAN KIN ONN ◽  
EVAN QUAH ◽  
MOHD ABDUL MUIN ◽  
ANNA E. SAVAGE ◽  
...  

A new, diminutive species of Rock Gecko, Cnemaspis shahruli sp. nov. from Penang Island, Penang; Pulau Jerejak, Penang; Pulau Pangkor, Perak; and the adjacent mainland at Sungai Sedim, Kedah was previously confused with juveniles of the sympatric, endemic species C. affinis (Stoliczka) on Penang Island. Cnemaspis shahruli sp. nov. is diagnosed from all other Southeast Asian Cnemaspis on the basis of several unique aspects of squamation, coloration, and body size. It is proposed that this new species has a more extensive mainland distribution than is presented here based on its southernmost record on Pulau Pangkor, Perak. A pattern of resource partitioning on the basis of body size, habitat, and activity period among sympatric species pairs of Cnemaspis is discussed.


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1336
Author(s):  
Andrzej Borkowski

The pine shoot beetles Tomicus piniperda L. and T. minor Hartwig are sympatric species that occur on Scots pine in two habitats. Feeding by the beetles in tree crowns causes significant losses in tree growth and disturbs the crown’s proper development. A review of the subject literature showed that there had been no previous studies of interspecific competition in stands with different degrees of crown damage. The aim of this work was to assess the resource partitioning of stems by the two species in stands with damaged and undamaged crowns. Data were collected in the years 1992–2008 in stands containing Scots pine located at different distances from timber yards. A total of 259 natural traps were laid, and measurements of height and diameter at breast height were made for 900 pines. The surface area of each stem was divided into 20 equal sections by making a division lengthwise (into units) and laterally (into an upper and lower part). In total, 90,501 egg galleries of pine shoot beetles were counted on 9560 stem sections. Feeding by pine shoot beetles in the crowns of pines reduces site productivity and the nutritional suitability of stems. The results of niche segregation indicate pine shoot beetles exhibited spatial specialization in the use of resources. prefers the thicker part of the stem, and T. minor the thinner part. The population of T. piniperda on the trap logs was described using a multiple linear regression model with three explanatory variables. As a result of regression modelling, from the set of variables representing characteristics of habitats, trees and trap logs and the parameters of infestation, the following explanatory variables were selected: range of colonisation of a trap log (rc), site quality class (sqc), and crown undamaged (cu). The explanatory variables included in the MLRM model explain to a significant degree (p < 0.05) the niche breadth of T. piniperda on trap logs. In all validated plots, the mean real and model values for the niche of T. piniperda on the trap logs are similar (p > 0.5), confirming the high accuracy of the developed model.


2009 ◽  
Vol 21 (2) ◽  
pp. 89-100 ◽  
Author(s):  
L. Zhang ◽  
Y.-B. Zhou ◽  
C. Newman ◽  
Y. Kaneko ◽  
D.W. Macdonald ◽  
...  

2000 ◽  
Vol 132 (2) ◽  
pp. 183-195 ◽  
Author(s):  
Daniel R. Miller ◽  
John H. Borden

AbstractMonoterpenes affected the attraction of three sympatric species of bark beetles (Coleoptera: Scolytidae) to pheromone-baited multiple-funnel traps in stands of lodgepole pine. Catches of Ips pini (Say) in traps baited with its pheromone, ipsdienol, were directly related to the release rates of 3-carene, β-phellandrene, and β-pinene. Catches of Dendroctonus ponderosae Hopkins in traps baited with exo-brevicomin and cis- and trans-verbenol were directly related to the release rates of 3-carene, myrcene, and β-phellandrene. Ips latidens (LeConte) exhibited preferences for traps baited with ipsenol and β-phellandrene or β-pinene but not in a dose-dependent fashion. Catches of I. latidens in traps baited with its pheromone, ipsenol, were inversely proportional to the release rates of 3-carene, myrcene, and terpinolene. Similarly, catches of I. pini in traps baited with its pheromone, ipsdienol, were inversely proportional to the release rates of myrcene and terpinolene. These results demonstrate a degree of species specificity among three phloeophagous species with respect to preferred host odours. The bark beetle predators–associates Lasconotus complex LeConte (Coleoptera: Colydiidae) and Corticeus Piller and Mitterpacher sp. (Coleoptera: Tenebrionidae) demonstrated some measure of specificity to monoterpenes in their responses to ipsdienol-baited funnel traps. γ-Terpinene increased attraction of L. complex but had no effect on Corticeus sp., whereas α- and β-pinene increased attraction of Corticeus sp. but had no effect on L. complex.


2017 ◽  
Vol 44 (3) ◽  
pp. 219 ◽  
Author(s):  
Michael A. Welsh ◽  
J. Sean Doody ◽  
Arthur Georges

Context Resource partitioning of diet and microhabitat was examined for five sympatric species of freshwater turtles in the Daly River in the northern end of Northern Territory (Top End) in Australia. The Daly River supports a high diversity of freshwater turtles, making it the ideal place to study a freshwater turtle community. Aims To determine the dry-season diet and microhabitat use of Carettochelys insculpta, Elseya dentata, Chelodina oblonga, Emydura victoriae and Emydura subglobosa worrelli and examine intraspecific and interspecific niche overlap and ontogenetic dietary shift. Methods Gut contents were collected by stomach flushing, and microhabitat use was determined by recording where each turtle was first seen before capture. Diet and microhabitat use were compared using an index of relative importance. Niche overlap was measured with Horn’s overlap index. Key results Carettochelys insculpta is an opportunistic omnivore that feeds mostly on ribbonweed (Vallisneria spiralis) and aquatic snails. Elseya dentata is herbivorous, feeding primarily on aquatic algae. The diets of C. insculpta and E. dentata overlapped moderately, but the overall niche overlap was low because they occupied different microhabitats within the river. Chelodina oblonga fed very little, and may use the Daly River as a dry-season refuge. Emydura victoriae is molluscivorous, consuming more molluscs as it grows. This ontogenetic dietary shift was associated with megacephaly (extreme broadly expanded head that is too large to fit into the carapace) and expanded triturating surfaces. This specialisation allows adult E. victoriae to feed exclusively on molluscs and so their diet overlapped little with other species. Emydura subglobosa worrelli was omnivorous, consuming mostly freshwater sponge and apparently preferring more lentic water. Conclusions The freshwater turtles of the wet–dry tropics are usually reported as being heavily reliant on the seeds, fruits and leaves of riparian vegetation; however, the present study showed that the dry-season diet in perennial rivers is primarily of aquatic origin. Implications The study suggested that populations of C. insculpta, E. dentata and E. victoriae could be threatened by broad-scale development in northern Australia if there were substantive impacts on aquatic macrophytes and molluscs in the Daly River system.


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