Search

In oscines, male song stimulates female reproduction and females are known to adjust both their sexual preferences and their maternal investment according to song quality. Female domestic canaries are especially responsive to wide frequency bandwidth (4 kHz) male songs emitted with a high-repetition syllable rate and low minimal frequencies (1 kHz). We previously showed that low-frequency urban noise decreases female sexual responsiveness for these low-frequency songs (1-5 kHz) through auditory masking. Based on the differential allocation hypothesis, we predicted that urban noise exposure will equally affect female maternal investment. Using a crossover design, we broadcast low-frequency songs to females either in an overlapping noise condition or in an alternating noise condition. Females decreased both their sexual responsiveness and their clutch size in the overlapping noise treatment relative to the alternative noise treatment. No differences were found concerning egg size or egg composition (yolk and albumen mass, testosterone concentration). Due to our experimental design, we can exclude a general impact of noisy conditions and thereby provide evidence for a detrimental effect through masking on avian courtship and reproductive output. These results suggest that noisy conditions may also affect avian communication in outdoor conditions, which may partly explain field reports on noise-dependent breeding success and reduced breeding densities at noisy sites. [ABSTRACT FROM AUTHOR]

Maternal effects play an important role in mediating reproductive success; the different allocation of resources in eggs is considered a primary maternal effect. In oviparous vertebrates, there are several substances (hormones, immunoglobulins, antioxidants, antibacterial molecules) that females may allocate differentially. Mate choice is a key factor influencing female reproductive decisions and investment in eggs, but it is not clear to what extent the dominance status of the partner can influence the decision to invest differentially in the quality of eggs. In the grey partridge Perdix perdix, we ranked males for their social status after pairwise dominance tests. Then, females were paired experimentally with dominant or subordinate individuals. We measured testosterone, lysozyme and ovotransferrin concentrations in their eggs. Females paired with dominant males laid eggs with higher testosterone concentration, while egg mass, lysozyme and ovotransferrin concentrations did not differ. With regard to testosterone, because this hormone has been shown to elicit beneficial effects in offspring hatching from grey partridge eggs, our results are in line with the differential allocation hypothesis that females paired with high-quality males should invest more in the current reproductive event. [ABSTRACT FROM AUTHOR]

Genetic introgression with exotic genomes represents a major conservation concern for the red-legged partridge ( Alectoris rufa, Phasianidae). In particular, massive releases of chukar partridges ( Alectoris chukar) and/or red-legged × chukar partridge hybrids for hunting purposes have cast serious doubts on the Italian present-day occurrence of wild A. rufa populations not affected by introgressive hybridization. This study investigates the genetic structure of red-legged partridges populations in two ecologically different areas in Northern Italy. Analysis of maternal mitochondrial DNA and biparental microsatellite markers excluded the presence of hybridization in a typical agricultural habitat where hunting and release of reared birds are strictly banned. By contrast, signs of chukar introgression were detected in a perifluvial habitat unusual for the red-legged partridge in Italy. The present study documents the first red-legged partridge population with no genetic evidences of recent chukar introgression presently living in Italy. We recommend that urgent conservation actions are taken to preserve the genetic integrity of this population from the risk of hybridization with farm-reared birds and to support its long-term conservation. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the possible trade-off between immune response, self maintenance, and reproductive output in grey partdriges in Alessandria, Italy. A total of 24 breeding pairs of grey partridges, Perdix perdix, were the subject of the study. Findings of the study suggest that an immune challenge can have physiological consequences in terms of self-maintenance and reproductive allocation to the egg, also stressing the need of further studies to provide a more complete picture of the long-term effects of immune challenge in a transgenerational perspective.

Females invest differently in their eggs depending on the quality of their mates. In oscines, female investment is influenced by the quality of male song. In domestic canaries Serinus canaria, as well as in black-capped chickadees Poecile atricapillus, females pay attention not only to the intrinsic quality of male song but can also gather information, by eavesdropping on male–male singing interactions, on the relative quality of males. During these interactions, overlapping the song of the rival is more threatening than alternating. Moreover eavesdropping female canaries have been shown to prefer the overlapping song rather than the overlapped song. The present study was designed to assess the effect of the information gathered by eavesdropping on female investment in eggs. First, we broadcasted overlapping interactions to female canaries. Then, we broadcasted to each female one of the two songs previously heard and collected eggs. Females exposed to overlapping songs laid eggs with greater yolk ratio than females exposed to overlapped songs. In contrast, yolk testosterone quantity and concentration were not affected by the treatment. Moreover, we found a variation between eggs with regard to the testosterone deposited in yolk: both quantity and concentration increased with laying order. Our results suggest that female canaries use information gathered by eavesdropping to differentially allocate resources into the eggs. They suggest that singing interactions could influence chick quality via female investment. [ABSTRACT FROM AUTHOR]

Vertebrate carrions, in particular fish, can provide a significant source of organic matter to lotic systems. Most studies related to animal matter degradation have been undertaken in Western North America, where entire lotic networks depend on large masses of anadromous salmonids, but less is known of other aquatic environments. In this study, the decomposition process of trout was analyzed in a Northern Italian stream, investigating the different importance of macro (invertebrates)—and micro (fungi)—consumers. Trout carcasses exhibited an exponential mass loss over time and attracted a rich community of microbic and invertebrate colonists. Final values for fish decay were significantly affected by the presence of macro-consumers; nevertheless, the role of macroinvertebrates seems to be not as predominant as in other ecological systems. Our study indicates that in lotic environments, which lack specialized necrophagous or sarcophagous invertebrate taxa equivalent to those found in terrestrial environments (such as maggots or carrion beetles), micro-consumers play a main role in fish carrions decomposition. [ABSTRACT FROM AUTHOR]

Feeding habits of larval Isoperla carbonaria Aubert, 1953 have been investigated in the Rio Alpetto, an Alpine creek of northwestern Italy. This species is characterised by relatively small size and rheophilous habits, and inhabits streams above 350 m a.s.l. in the Alps, Apennines and Sicily. In this study, we analysed the gut contents of 72 larvae of this species, with the aim of investigating feeding preferences and to assessing the existence of size-related shifts in the trophic spectrum. Larvae were collected from a single reach, whose benthic coenosis was also determined. We detected evident trophic preferences in the diet: few taxa constituted the greatest part of the ingested items, independently from their availability in the substratum. Moreover, we observed that largest larvae fed on a broader number of taxa. These findings are discussed and compared with data obtained from other Systellognatha species. [ABSTRACT FROM AUTHOR]

In this study we investigated the emergence patterns of two Systellognatha stoneflies: Perla marginata and P. grandis (Plecoptera: Perlidae) in a first order stream of the Northern Apennines (NW Italy). Exuviae of both species were collected in a selected area of the Curone creek by hand-picking, measuring the distance between river edge and substrate typology. Exuviae were found on different substrate types near the shoreline: stones in the stream bank were mainly used by both species, and gravel beach was the least-utilised substrate. No evident differences were found between the species in the typology and colour of emergence substrates. Interestingly, we found that P. grandis exuviae were significantly located at greater horizontal and vertical distances from the water edge than P. marginata ones. We discuss these findings on the basis of ecological and behavioural considerations. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We examined vertical migration and colonisation patterns of stream macroinvertebrates within the substratum of an Apennine creek in NW Italy. Macrobenthos was sampled at three depths in the streambed (0–5, 5–10, 10–15 cm) by means of artificial baskets filled with natural substratum. We placed 42 traps (5×5×15 cm), i.e. 21 top-opened (T-traps) and 21 bottom-opened (B-traps), each composed of three overlapping baskets (high-H, medium-M and low-L), to evaluate differences in the vertical movements. We also collected Surber samples to compare interstitial assemblages with streambed communities. The multilevel traps yielded 42 taxa, compared with 60 taxa in the natural riverbed. Interstitial traps were rapidly colonised; both taxa richness and organism number increased during the 42-day study period. We found active migration in both vertical directions, but there were more invertebrates in the top-opened traps than in the bottom-opened traps. In the T-traps the most colonised baskets were those placed at the H level, while in the B-traps the L level baskets were more rapidly colonised. The interstitial assemblages differed markedly from the streambed communities in both composition and functional organisation, with more collector-gatherers and predators in the interstitial zone and more filterers and scrapers in the natural riverbed. In Apennine lotic systems, the interstitial zone is an important habitat for stream macrobenthos, although it may not be used by all species. [ABSTRACT FROM AUTHOR]

Steam disinfestation of soil is attracting growing interest in intensive agriculture, because of the increasing demand of reduced use of fumigants. In this study, we assessed the effect of steam application on the microarthropod community, a fundamental component of soil environment. We conducted steam disinfestation treatments in experimental parcels, where we sampled for edaphic microarthropods on one date before and on four dates after the treatments. Our results showed that edaphic fauna quickly recolonized the disinfested soil, re-establishing dense and rich communities after 45 days. These results support the low environmental impact of this technique and could be used for certification of the eco-biological sustainability of steam treatment in organic farming. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We described the microdistribution of benthic macroinvertebrates in a 50 m riffle segment of the Rio del Giovo (Sassello, NW Italy) during a period of rapid loss of leaf mass, from March to May 2003. We analyzed the relationship between the taxonomic composition and functional organization of benthic communities and the availability of coarse particulate organic matter (CPOM), as well as the influence of micro-environmental characteristics (water velocity, depth, and substratum). Patches without CPOM hosted specialized communities. The temporal variation of CPOM influenced the distribution of functional feeding groups in the riverbed. In particular, shredder assemblages were widespread in the riverbed when CPOM was abundant, but when this resource became scarce and localized, their density was related to the availability of allochthonous organic detritus. [ABSTRACT FROM AUTHOR]

It has been shown that small passerines can counteract variability of food resources by actively regulating their body reserves through an increase of mass. However, the effects of food predictability on body mass regulation and other body parameters, such as immune functions, in larger species have been little studied. To analyse the response of the Hooded Crow Corvus corone to food abundance and predictability, we performed three experiments with controlled food provisioning under laboratory conditions. Body mass, TOBEC (total body electrical conductivity) lean mass index, blood parameters and immune organ masses were measured at the beginning and end of a 15-day period. In the first experiment, the food release was predictable (same amount each day) but the quantity of food delivered to five groups of birds varied (37, 75, 100, 150 or 300 g/day). Low food levels induced a greater decrease in mass accompanied by an increase in erythrocyte sedimentation rate. In the second experiment, the same average quantity of food (100 g) was supplied according to either predictable or unpredictable (random) schedules. In this case, the crows lost more mass, and their erythrocyte sedimentation rate increased when food was unpredictable. In the third experiment, the same average quantity of food (150 g) was supplied according to either a predictable schedule or two schedules with different levels of variability. The group with a low level of variability did not differ from the control, while the group with a highly variable feeding schedule lost more mass. In this group, the higher mass loss was associated with greater variation of the erythrocyte sedimentation rate and a reduced Phytohaemagglutinin index of immunocompetence and haematocrit value. The results of experiments 2 and 3 contrast with findings in other passerines, which increase their mass when food availability is unpredictable. It appears that a body mass decrease in the Hooded Crow can be induced by a reduction of either food abundance (exp. 1) or food predictability (exp. 2, 3), and it is accompanied by a worsening of health state. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Studies the bill characteristics and body condition in the Moorhen, Gallinula chloropus. Important role played by carotenoids in animal collaboration; Signals of general health conditions.

Focuses on a study which analyzed song differences between adults and subadults Black Redstart or Phoenicurus ochruros. Methodology; Difference between adult and subadult song; Results of the playback experiment conducted.