scholarly journals Influence of ambient humidity on the attachment ability of ladybird beetles (Coccinella septempunctata)

2016 ◽  
Vol 7 ◽  
pp. 1322-1329 ◽  
Author(s):  
Lars Heepe ◽  
Jonas O Wolff ◽  
Stanislav N Gorb

Many insects possess adhesive foot pads, which enable them to scale smooth vertical surfaces. The function of these organs may be highly affected by environmental conditions. Ladybird beetles (Coccinellidae) possess dense tarsal soles of tenent setae, supplemented with an adhesive fluid. We studied the attachment ability of the seven-spotted ladybird beetle (Coccinella septempunctata) at different humidities by horizontal traction experiments. We found that both low (15%) and high (99%) relative humidities lead to a decrease of attachment ability. The significantly highest attachment forces were revealed at 60% humidity. This relationship was found both in female and male beetles, despite of a deviating structure of adhesive setae and a significant difference in forces between sexes. These findings demonstrate that not only dry adhesive setae are affected by ambient humidity, but also setae that stick due to the capillarity of an oily secretion.

2011 ◽  
Vol 2 ◽  
pp. 302-310 ◽  
Author(s):  
Elena V Gorb ◽  
Stanislav N Gorb

The slippery zone in pitchers of the carnivorous plant Nepenthes alata bears scattered prominent lunate cells and displays continuous epicuticular crystalline wax coverage. The aim of this study was to examine the influence of the surface anisotropy, caused by the shape of lunate cells, on insect attachment ability. Traction tests with ladybird beetles Coccinella septempunctata were performed in two types of experiments, where surface samples of (1) intact pitchers, (2) chemically de-waxed pitchers, and (3) their polymer replicas were placed horizontally. Beetle traction forces were measured when they walked on test surfaces in either an upward (towards the peristome) or downward (towards the pitcher bottom) direction, corresponding to the upright or inverted positions of the pitcher. On intact pitcher surfaces covered with both lunate cells and wax crystals, experiments showed significantly higher forces in the direction towards the pitcher bottom. To distinguish between the contributions, from claw interlocking and pad adhesion, to insect attachment on the pitcher surfaces, intact versus claw-ablated beetles were used in the second type of experiment. On both de-waxed plant samples and their replicas, intact insects generated much higher forces in the downward direction compared to the upward one, whereas clawless insects did not. These results led to the conclusion that, (i) due to the particular shape of lunate cells, the pitcher surface has anisotropic properties in terms of insect attachment, and (ii) claws were mainly responsible for attachment enhancement in the downward pitcher direction, since, in this direction, they could interlock with overhanging edges of lunate cells.


2016 ◽  
Vol 123 (1) ◽  
Author(s):  
Lars Heepe ◽  
Dennis S. Petersen ◽  
Lisa Tölle ◽  
Jonas O. Wolff ◽  
Stanislav N. Gorb

2016 ◽  
Vol 7 ◽  
pp. 1471-1479 ◽  
Author(s):  
Matt W England ◽  
Tomoya Sato ◽  
Makoto Yagihashi ◽  
Atsushi Hozumi ◽  
Stanislav N Gorb ◽  
...  

The attachment ability of ladybird beetles Coccinella septempunctata was systematically investigated on eight types of surface, each with different chemical and topographical properties. The results of traction force tests clearly demonstrated that chemical surface properties, such as static/dynamic de-wettability of water and oil caused by specific chemical compositions, had no significant effect on the attachment of the beetles. Surface roughness was found to be the dominant factor, strongly affecting the attachment ability of the beetles.


Ecotoxicology ◽  
2016 ◽  
Vol 25 (10) ◽  
pp. 1782-1793 ◽  
Author(s):  
Da Xiao ◽  
Jing Zhao ◽  
Xiaojun Guo ◽  
Hongying Chen ◽  
Mengmeng Qu ◽  
...  

2009 ◽  
Vol 69 (1) ◽  
pp. 41-48 ◽  
Author(s):  
FG. Araújo ◽  
MG. Peixoto ◽  
BCT. Pinto ◽  
TP. Teixeira

Cyprinodontiformes fishes (guppies) are widely distributed in Neotropical regions and use deteriorated microhabitats in rivers where few species can occur. This study was carried out in a stretch of the Paraíba do Sul River in bracketing a large urban-industrial complex. The aim was to assess eventual effects that the industrial complex could have on distribution of two closely related fish species of guppies, Phalloceros caudimaculatus and Poecilia reticulata. The area was divided into three zones: Z1, 40 km upriver of the major urban-industrial complex of Volta Redonda; Z2, just down river of the complex; and Z3, 30 km down river of the complex. Six sites (two in each zone) were sampled monthly between November 1998 and October 1999, using a standardized fishing effort with cast net throws, trays lifts and seine hauls, covering different microhabitats, that is, riffles, pools and the proximity of the river's margins. Poecilia reticulata was widely distributed, peaking at Z2, the most polluted area, while P. caudimaculatus showed the highest abundance at Z3, being almost absent in Z1. Both species occurred in high numbers throughout the year but they were scarce between April and June. Females outnumbered males for both species in most size classes and at all sites. Juveniles were more abundant than adults, with non-pregnant females outnumbering pregnant ones. Condition factor was always higher in males than females but only males P. reticulata showed significant difference among the three zones, with the highest values at Z2. The higher number of females confirms the expectation that these species can use very polluted areas and that availability of food provided by organic loads allowed their distribution all over the area. Although these two species have shown indication of spatial separation in the study area, their similar seasonal patterns of occurrence suggest that they respond in a similar way to changes in environmental conditions.


2021 ◽  
Vol 50 (1) ◽  
pp. 65-74
Author(s):  
Loris Galli ◽  
Franc Janžekovič ◽  
Peter Kozel ◽  
Tone Novak

Protura is a small class of Hexapoda, generally poorly known, and rather scarce data on its occurrence in caves are scattered throughout literature on fauna in caves and in some papers on Protura. Although the cave-dwelling fauna is relatively well studied in Slovenia, published records on Protura are rare. In this paper, data on the occurrence and abundance of Protura in Slovenian caves are considered. Various statistical analyses were performed to compare caves with Protura to those without in 60 intensively monitored cavities to detect any differences in the selected environmental conditions. No significant difference was obtained. Samples collected from 15 caves yielded 286 specimens identified to genus or species level. Ten species were identified: Acerentulus confinis (Berlese, 1908), A. rafalskii Szeptycki, 1979*, Acerentomon affine Bagnall, 1912*, A. balcanicum Ionesco, 1933*, A. italicum Nosek, 1969, A. maius Berlese, 1908*, A. meridionale Nosek, 1960, Acerella muscorum (Ionesco, 1930)*, Eosentomon armatum Stach, 1926*, and E. transitorium Berlese, 1908*. The seven species marked with an asterisk are new records for Slovenia. Two specimens belonging to an unidentified species of the genus Ionescuellum Tuxen, 1960 were also found. As expected, Protura were most abundant at the cave entrance close to the surface, and none of the species were found exclusively in cavities. This suggests that proturans were introduced passively into the cavities via organic matter and surface soils.


2021 ◽  
Vol 17 (2) ◽  
pp. 77-89
Author(s):  
Jessico H Sermatang ◽  
Charlotha I Tupan ◽  
Laura Siahainenia

Seagrass as a flowering plant can live from muddy substrates to coral fractures. Differences in the characteristics of substrate type, nutrient content and aquatic environmental conditions can affect morphometric seagrass. The purpose of the study was to analyze environmental conditions and nutrient content as well as the morphometric characteristics of T. hemprichii seagrass based on differences in substrate type. This study was conducted in the waters of Tanjung Tiram Coastal, Poka from February-April 2021. Seagrass sampling was using the purposive sampling method. Data analysis was conducted using ANOVA with SPSS. The results of environmental parameters analysis showed that the water conditions of Tanjung Tiram, Poka are still at the tolerance limit intended for seagrass life. The substrate consists of sand substrate, gravel mixed sand substrate and mud substrate. The results of ANOVA showed that there was a significant difference in the content of sedimentary nutrients, especially phosphates in each substrate type and there was a significant difference in morphometric seagrass based on differences in substrate type and nutrient content.   ABSTRAK Lamun sebagai tumbuhan berbunga dapat hidup mulai dari substrat berlumpur sampai dengan patahan karang. Perbedaan karakteristik jenis substrat, kandungan nutrien dan kondisi lingkungan perairan dapat mempengaruhi morfometrik lamun. Tujuan dari penelitian ini adalah menganalisis kondisi lingkungan dan kandungan nutrien serta karakteristik morfometrik lamun T. hemprichii berdasarkan perbedaan tipe substrat. Penelitian ini dilaksanakan di Perairan Pantai Tanjung Tiram, Poka pada Bulan Februari-April 2021. Pengambilan sampel lamun menggunakan metode purposive sampling. Analisis data menggunakan ANOVA dengan SPSS. Hasil analisis parameter lingkungan, menunjukan bahwa kondisi perairan Tanjung Tiram, Poka masih berada pada batas toleransi yang diperuntukan untuk kehidupan lamun. Substrat terdiri dari substrat pasir, pasir campur kerikil dan lumpur. Hasil anova menunjukan bahwa terdapat perbedaan kandungan nutrien sedimen khususnya fosfat secara signifikan pada masing masing tipe substrat dan terdapat perbedaan morfometrik lamun secara signifikan berdasarkan perbedaan tipe substrat dan kandungan nutrien. Kata Kunci: morfometrik, nutrien, substrat, Tanjung Tiram, Thalassia hemprichii


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