Trophic eggs, which are not viable and eaten by larvae, are produced by the passalid beetle Cylindrocaulus patalis. This is the first record of trophic eggs in subsocial Coleoptera. There are differences in the morphology of trophic and fertile eggs; the former are a paler colour and softer than the latter. The surface of the chorion of trophic eggs is also smoother than that of fertile eggs. The trophic eggs are fed directly by the female parent to 3rd instar larvae following a series of specific behavioural interactions between them, including repeated stridulation by the larva. It is likely that trophic eggs supplement the protein-poor diet of the larvae and contribute to their growth and survival. The production of trophic eggs may be associated with the evolution of an extremely small clutch size in C. patalis.
The Joaquín Costa reservoir contains a mixed fish assemblage of native and exotic species. Feeding habits and feeding relationships of species in the fish assemblage were analysed over a one year cycle. Differences in diet composition were found both between species and within species among seasons. Food overlap and trophic similarity among species also showed seasonal variations. Cluster analysis differentiated four groups of predominant diet: (1) macroinvertebrates (trout and largemouth bass), (2) detritus (nase), (3) cladoceran crustaceans and (4) an omnivorous feeding regime, with large seasonal variations in food habits. Food of fish species included in groups 3 and 4 (roach, white bream, barbel, common and mirror carp) varied seasonally. Using graphical models of feeding strategies, similarity indexes, cluster and multivariate analyses based on the relative importance of food categories in the diet of the species, we illustrate that the fish assemblage showed food resource partitioning according to food habits and foraging habitats within the reservoir.
Ovipositing females from invasive (Krasnodar Territory of Russia) and native (Far East of Russia) populations of Harmonia axyridis were fed one of a set of diets ranging from 50 Myzus persicae aphids every day to 1 aphid every 10 days and all were also provided with a 10% sugar solution. The experiment was conducted at 20°C under short (12 h) and long (18 h) day conditions. Most of the females from the native population that consumed 50 or 10 aphids per day continued to oviposit under both long and short day conditions. Females that consumed 1 aphid per day or every 2 days practically stopped laying eggs but under long day conditions their ovaries were still active, whereas under short day conditions ca 50% of them were reproductively inactive (only germaria present) and had a well-developed fat body. Further reduction in diet resulted in an increase in the proportion of reproductively inactive females. However, about half of the females that terminated oogenesis under long day conditions had poorly developed fat bodies, which indicates that diapause was not induced. For the females from the invasive population, both photoperiodic and trophic effects were weak: under short day conditions, some females entered diapause when prey was abundant, whereas about 50% (independent of photoperiod) did not enter diapause when starved. This risk-spreading strategy, possibly, facilitates the adaptation of this invasive ladybird to unpredictable environmental conditions., Antonina A. Ovchinnikova, Andrey N. Ovchinnikov, Margarita Yu. Dolgovskaya, Sergey Ya. Reznik, Natalia A. Belyakova., and Obsahuje bibliografii
1_The arboricolous dolichoderine ant Liometopum microcephalum (Panzer, 1798) is considered to be mainly predatory, although there are some reports of it tending aphids. The main objective of the present study was to confirm that this ant has a trophobiotic relationship with aphids and assess seasonal differences in its utilization of honeydew. We hypothesized that the worker ants on trees where they have their nest (nest tree) and trees where they are foraging (foraging trees) should differ in gaster mass and sugar content depending on their direction of movement, and that both should be highest in spring. From spring to summer 2009, ascending and descending workers were collected from nest and foraging trees at a locality in South Moravia, Czech Republic. Mass of their gasters and their content of total and reducing sugars were measured using chemical (photometric) methods. Differences in gaster mass confirmed the flow of liquid food from foraging to nest trees, but there were no significant between-month differences. Contents of total and reducing sugars were positively correlated with gaster mass. The gasters of workers descending from foraging trees contained significantly more reducing sugars than those of workers descending or ascending nest trees. The content of reducing sugars was lowest at the beginning of the ants’ activity period in April and highest in June, with a non-significant drop in July. Results for total sugars were similar, with the decrease in July being significant. The concentration of sugars in the gasters of workers ascending and descending nest trees did not differ significantly but the absolute content of total sugars was higher in the gasters of ascending ants., 2_Results from foraging trees confirmed that the ants collected the honeydew from these trees. Possible reasons for the ambigous results for nest trees are discussed. We conclude that trophobiosis is an important component of the nutritional biology of L. microcephalum., Jiří Schlaghamerský ... []., and Obsahuje seznam literatury
We recorded the association between the planthopper Tettigometra laetus Herrich-Schäffer, 1835 (Hemiptera: Fulgoromorpha: Tettigometridae) and three ant species belonging to the subfamilies Myrmicinae and Formicinae in a coastal dune area of Flanders (Belgium). Lasius psammophilus Seifert, Tetramorium caespitum L. and Formica cunicularia Latreille were observed attending and palpating the dorsal glandular area of this planthopper, taking honeydew directly from its anus, herding them and carrying them into their nests when disturbed. The planthopper was rarely found in the absence of ants and probably develops within ant nests, which may provide protection against predation and adverse weather conditions. The natural history of temperate ant-hemipteran relationships is discussed.
Tropické lesy ostrova Borneo v jihovýchodní Asii jsou celosvětově výjimečné vysokou biodiverzitou různých skupin organismů. Jejich podoba byla formována mimo jiné během čtvrtohorního kolísání hladiny světových oceánů, kdy byly ostrovy sundské oblasti vzájemně propojeny či odděleny, což mělo vliv na migraci organismů. Současná diverzita lesů Bornea sleduje gradient nadmořské výšky a vlastnosti substrátů, přičemž můžeme rozlišit několik hlavních typů lesa. V posledních desetiletích jsme svědky masivní těžby lesů, které jsou mnohde převáděny na plantáže palmy olejné., Tropical forests of the island of Borneo in South East Asia harbour an extraordinary high biodiversity of various groups of organisms. They have been shaped, among other influences, by the Quaternary fluctuations of the level of world’s oceans, connecting or dividing islands within the Sundaland, which has affected migration of species. The present diversity of forests in Borneo follows an elevational gradient and substrate properties, thus forming several main forest types. Over the past few decades, we have witnessed massive logging and transformation of forests into oil palm (Elaeis guineensis) plantations., Radim Hédl., and Obsahuje seznam literatury
In a series of articles, we have been developing a theory of \emph{tropical diagrams of probability spaces}, expecting it to be useful for information optimization problems in information theory and artificial intelligence. In this article, we give a summary of our work so far and apply the theory to derive a dimension-reduction statement about the shape of the entropic cone.
Forest dynamics, taxonomic diversity and synchronization of flowering are important ecological aspects of woody species of tropical forests in Borneo. Repeated measurements on permanent plots show that forest dynamics are driven by gap formation. Attempts have been made to explain high tropical diversity by a number of theories, ranging from the ecological equitability of species to narrow niche specialization. Finally, the conspicuous flowering synchronicity, principally of three species of the family Dipterocarpaceae, may be explained as a reaction on predation in regeneration phase. This phenomenon is triggered by climatic fluctuations connected to the El Nino-Southern Oscillation.
Borneo je ostrovem se zajímavou geomorfologií a překvapivě různorodou geologií. Oba faktory se spolu s historickým vývojem určujícím migrace druhů podílely na současné pestrosti bornejské flóry. Pozoruhodné funkční a taxonomické skupiny rostlin najdeme nejen v zapojeném lese, ale také nad horní hranicí lesa, v pobřežních prostředích, podél vodních toků a jinde. V krátkosti jsou představeny vybrané funční skupiny epifyty, epifyly, liány, masožravé rostliny s význačným rodem láčkovka, nezelené rostliny, rheofyty a alpinské rostliny, mezi kterými nalezneme i trávy temeprátních oblastí. Z pozoruhodných taxonomických skupin představujeme zázvory, áronovité, begonie a pěnišníky, které mají na Borneu jedno z center své diverzity., Borneo is an island with conspicuous geomorphology and variable geology. Both factors have contributed, along with historical development determining species migrations, to the present richness of the flora of Borneo. Remarkable functional and taxonomic groups of herbs occur not only in closed forests, but also above the timberline, in coastal and riparian habitats, and elsewhere. Selected functional groups are briefly introduced: epiphytes, epiphylles, rheophytes, carnivorous, achlorophyllous and alpine plants. From conspicuous taxonomic groups, we introduce gingers, aroids, begonias and rhododendrons., and Martin Dančák ... [et al.].