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1. Depilation increases while hairiness decreases the risk of drowning: a hitherto unappreciated survival role of setae in woolly bear caterpillars of the moth Lemyra imparilis (Lepidoptera: Noctuoidea: Erebidae)

Creator:
Meyer-Rochow, V. Benno
Format:
print, počítač, and online zdroj
Type:
article, články, journal articles, model:article, and TEXT
Subject:
Zoologie, motýli, butterflies, Lepidoptera, Erebidae, Lemyra imparilis, insect setae, cuticle, wettability, floating, 2, and 59
Language:
English
Description:
This note aims to put on record a hitherto unreported function of caterpillar setae supplementary to those already known. When woolly bear caterpillars of the moth Lemyra imparilis (Butler) have their body hairs removed and are dropped into a bucket of water from a height of 30 cm, they sink immediately. Caterpillars, however, with an intact coat of hairs usually float. This hitherto unreported role of caterpillar setae as life-rafts should depend on a high contact angle θe, and thus on the position, density and dimensions of the hairs. An SEM examination of the surface structure of the setae revealed a system of fine grooves and small distally pointing barbs on the hair shaft, which can trap air to support the weight of the insect. Insect setae generally and body hairs of caterpillars in particular are known to possess many functions, but a role as life-rafts for caterpillars in danger of drowning can now be added to the list of possible uses of body hairs., V. Benno Meyer-Rochow., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Photosynthetic performance and water use efficiency of the fern Cheilanthes persica

Creator:
Gratani, L., Crescente, M. F., and Rossi, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
carotenoids, chlorophyll, cuticle, dehydration, desiccation tolerance, mesophyll, palisade and spongy parenchyma, stomatal conductance, and succulence
Language:
Multiple languages
Description:
Morphological, anatomical and physiological frond traits of Cheilanthes persica (Bory) Mett. ex Kuhn were studied to analyze its adaptive strategy. Mean frond life span is about 340 d. Mature fronds are characterized by 91 g m-2 areal dry mass (ADM) and 217 g m-2 succulence. The reduction of frond water content in July (dehydration phase) caused a 51 % decrease in frond surface area (SA). Fronds were dry in August (desiccation phase); nevertheless, in September they showed an increased SA (rehydration phase). Chlorophyll (Chl) a/b ratio, above 3, and the well developed palisade parenchyma (two layers, total thickness of 103.9 µm) are typical for sun leaves. Chl and carotenoid contents and net photosynthetic rate (PN) increased during frond development until the highest values in April-May (maturity phase). When mean air temperature reached 31.3 °C, stomatal conductance (gs) decreased by 34 % and PN by 33 %. The high pigment contents can dissipate the excess of radiant energy, particularly under unfavourable conditions, when PN is low. Rather high PN was found during the rehydration stage. The pronounced decline of mesophyll activity during the declining phase was confirmed by the lowest PN. and L. Gratani, M. F. Crescente, G. Rossi.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Thin layer chromatographic analysis of pteridine-like pigments in the migratory locust, Locusta migratoria migratorioides (Orthoptera: Oedipodidae)

Creator:
Němec, Václav, Breuer, Michael, and de Loof, Arnold
Type:
article, model:article, and TEXT
Subject:
Pterines, phase-transition, juvenile hormone, precocene, cuticle, methoprene, neem, and insect endocrinology
Language:
English
Description:
Acidic methanolic extracts of haemolymph, cuticle and eyes of larvae and adults of the migratory locust, Locusta migratoria migratorioides (R. et L.), were subjected to thin layer chromatography. The Rf-values as well as the fluorescent colour of the spots under ultraviolet illumination at 350 nm, were compared to those of 12 pteridine standards. Most of the standards showed a major spot, as well as up to 3 additional minor spots, probably due to the presence of isomers and degradation products. The extract of the haemolymph of untreated larvae and adults yielded 6 different spots. Cuticle and eyes had their own specific pattern. Application of methoprene (analogue of juvenile hormone) induced solitary phase-like pigmentation of the cuticle and green-coloured haemolyph. The content of pterin, biopterin, leucopterin, isoxanthopterin, and probably also of lumazin, increased. The melanization of the cuticle nearly completely disappeared. Similar, but weak effects were observed in neem-oil treated locusts. Application of precocene caused a number of changes in the pigment pattern of all extracts. It also induced some melanization of the cuticle in particular in larvae. Many pigment spots were observed which did not correspond to any of the 12 standard pteridines. The classical concept about the pigment composition of locust haemolymph, namely that it is restricted to melanin, carotenes and biliverdin, needs modification.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public