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21.
Kai Lindström Colette M. St. Mary Christophe Pampoulie 《Behavioral ecology and sociobiology》2006,60(1):46-51
Male parental care is typically thought to come at a cost to mate attraction and future mating success. However, it has also
been hypothesized that paternal care may be under sexual, as well as natural, selection, such that good fathers actually attract
more mates. Here we show experimentally that in the sand goby, Pomatoschistus minutus, females prefer to mate with males that provide higher levels of parental care. We manipulated male behavior using (1) different
nest sizes and (2) an application of low-O2 water in the nests, and found that females consistently preferred males with elevated levels of care in dichotomous mate
choice tests. This complements our earlier study in which we showed that males increase the amount and quality of care they
provide in the presence of females. Our results demonstrate that male care may have evolved as a result of sexual selection
rather than natural selection alone, and furthermore, that male care may not necessarily be in conflict with mate attraction. 相似文献
22.
Nest defence behaviours, such as attacking predators and defending against predator attacks, expose birds to risk of injury
and death. However, direct costs of such behaviours are poorly documented. To evaluate potential costs of nest defence behaviours
in lesser snow geese (Chen caerulescens), we (1) estimated the proportion of interactions between arctic foxes (Alopex lagopus) and geese that resulted in physical contact and (2) examined how nest defence behaviours varied between male and female
geese. We separated interactions into attacks initiated by foxes (attacks by foxes) and attacks initiated by geese (attacks by geese). Risks associated with attacks by geese were considerably lower than the risks associated with attacks by foxes; only 1
of 1,179 attacks by geese resulted in physical contact between foxes and geese, whereas 26 of 89 attacks by foxes involved
such contact (two female geese were killed during these attacks). Attacks by geese were made almost exclusively by male geese
(>97%), whereas female geese were involved in 75% of all attacks by foxes that resulted in physical contact with geese. There
was, thus, a considerable difference in risks associated with male and female nest defence behaviours. We suggest that parental
roles during nesting (i.e., females incubate and males guard) expose female geese to greater risk of injury and death. Male
geese may, however, reduce the risk of injury or death to their mates with pre-emptive attacks on foraging foxes. 相似文献
23.
An individually marked population of great reed warblers Acrocephalus arundinaceus was studied between 1984 and 1991 in South Central Sweden. The fates of 279 nests were analysed for the 25 days following clutch initiation. The average frequency of nest loss (43%) did not differ significantly between years or between four periods of the breeding season. After a breeding failure, 70% of the females laid a replacement clutch, most of them together with the same male. On polygnous territories, males assisted the female who first hatched young regardless of her initial mating status (Fig. 2). According to the acutal status of the females attending the nests, for each day nests were classified as being of either monogamous (M), primary (P) or secondary (S) status. From egg-laying to fledging the rate of nest loss decreased among nests of primary status whereas it increased among nests of monogamous and secondary status. During the egg-laying period, the rate of nest loss was 3 times higher among nests of primary than among nests of monogamous and secondary status (Fig. 3). Thus, the high loss level among nests of primary status during the laying period was closely associated with the presence of a female with a less advanced nest on the territory. All nests were situated in reed beds above deep water and most of them at a height at which possible inter-specific nest predators would have caused disturbance to the nest itself. The suspicion that secondary females committed sexually selected infanticide was supported by an experiment with dummy eggs that revealed bill peck markings identical to those obtained from great reed warblers (Fig. 4). 相似文献
24.
Tina Heger Anna T. Pahl Zoltan Botta-Dukát Francesca Gherardi Christina Hoppe Ivan Hoste Kurt Jax Leena Lindström Pieter Boets Sylvia Haider Johannes Kollmann Meike J. Wittmann Jonathan M. Jeschke 《Ambio》2013,42(5):527-540
Invasion ecology has much advanced since its early beginnings. Nevertheless, explanation, prediction, and management of biological invasions remain difficult. We argue that progress in invasion research can be accelerated by, first, pointing out difficulties this field is currently facing and, second, looking for measures to overcome them. We see basic and applied research in invasion ecology confronted with difficulties arising from (A) societal issues, e.g., disparate perceptions of invasive species; (B) the peculiarity of the invasion process, e.g., its complexity and context dependency; and (C) the scientific methodology, e.g., imprecise hypotheses. To overcome these difficulties, we propose three key measures: (1) a checklist for definitions to encourage explicit definitions; (2) implementation of a hierarchy of hypotheses (HoH), where general hypotheses branch into specific and precisely testable hypotheses; and (3) platforms for improved communication. These measures may significantly increase conceptual clarity and enhance communication, thus advancing invasion ecology. 相似文献
25.
Tropical arboreal ant mosaics: innate attraction and imprinting determine nest site selection in dominant ants 总被引:2,自引:0,他引:2
The modalities of nest site selection have, until now, been a key factor missing in the understanding of the arboreal ant
mosaic, the manipulation of which could be used to favour one ant species to the detriment of others in biological control.
We compared two dominant African arboreal ants of economic importance, Tetramorium aculeatum (Myrmicinae) and Oecophylla longinoda (Formicinae). The two species differed in terms of innate attraction to nesting site plants, their hierarchies of attractiveness
being nearly inverse. Winged females and workers were confronted with choice tests using four plant species. By using winged
females and workers originating from one of the plants to be tested, we showed the existence of a familiarisation process
which can supersede innate attraction in both species. We recorded the same effect in neonatal workers bred in the laboratory
in contact with a tested plant for 25 days after emergence, while mature workers could not be conditioned. There is, therefore,
early learning, with a sensitive period after which the influence of the environment ceases, suggesting that this is a true
imprinting process. Choice tests using neonates produced from larvae and pupae bred in the laboratory in contact with the
leaves of each tested plant permitted us to demonstrate the existence of pre-imaginal learning. Nest site selection therefore
depends on innate selective attraction and on environmental factors whose effect begins at the larval stage. There is, therefore,
the potential to “control” imprinting, allowing one ant species to be favoured to the detriment of others in monospecific
tree crop plantations.
Received: 25 May 1998 / Accepted after revision: 9 October 1998 相似文献
26.
安全管理系统工作平台建设与应用实践 总被引:5,自引:4,他引:1
谢宗明 《中国安全生产科学技术》2009,5(1):172-175
为了规范管理工厂安全制度文件体系,完善企业的安全管理制度,在对商业化安全管理软件分析的基础上,该文设计开发了适合自己企业的安全管理系统工作平台.其构架主要由综合设计、规章制度管理、审核检查管理、安全活动管理、安全资料、职业健康法律法规等九个模块构成,并对主要的三个模块进行了详细地介绍。这个平台系统设计和实施过程,促进了企业安全生产制度体系的整理和完善,为提高企业安全生产管理水平提供了又一种新的技术保障手段。 相似文献
27.
Gorbi Stefania Benedetti Maura Virno Lamberti Claudia Pisanelli Barbara Moltedo Ginevra Regoli Francesco 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):3166-3173
Diethylene glycol (DEG) is largely used during oil and gas exploitation by offshore platforms. The aim of this work was to investigate if this compound induces direct molecular/cellular effects in marine organisms, or indirectly modulate those of produced waters (PWs). Sea bass (Dicentrarchus labrax) were exposed to DEG dosed alone or in combination with PWs from an Adriatic platform. A wide array of analysed biomarkers included cytochrome P450-dependent enzymatic activity, bile metabolites, glutathione S-transferases, acetylcholinesterase, peroxisomal proliferation, antioxidant defences (catalase, glutathione reductase, glutathione peroxidases, glutathione), total oxyradical scavenging capacity, malondialdehyde and DNA integrity (single strand breaks and frequency of micronuclei). Results did not reveal marked effects of DEG, while PWs influenced the biotransformation system, the oxidative status and the onset of genotoxic damages. Co-exposures caused only limited differences of biomarker responses at some experimental conditions, overall suggesting a limited biological impact of DEG at levels normally deriving from offshore activities. 相似文献
28.
Enock Warinda Dickson M Nyariki Stephen Wambua Reuben M Muasya Munir A Hanjra 《Natural resources forum》2020,44(1):3-39
Investments in agricultural technologies, capacity building and policy harmonization are needed to support sustainable development across Africa. Regional development projects can facilitate the adoption of agricultural technologies and innovations across nation-state borders and generate benefits for shared prosperity. This paper uses panel data from 1,160 smallholder households including beneficiaries and non-beneficiaries from five countries in East Africa - Burundi, Kenya, Rwanda, Tanzania, and Uganda. From a pool of over 90 projects implemented over a span of 15 years, 23 regional projects are included in this study. The major economic benefits to smallholder participants are higher crop productivity and income, access to adaptable technologies, access to markets, higher livestock and milk production, gender equality, enhanced food security, resilience and capacity building for uptake and scaling up of future innovation platforms. For example, the adoption of low-cost tissue culture banana by the beneficiaries increased their incomes by 15% in Rwanda while the adoption of appropriate land and water management technologies increased the potato yields from 2.8 tons (USD 2,840/ha) to over 7.5 tons (USD 7,410/ha) in Kenya. The beneficiaries ensured value added to commodities like bananas (for export) and orange-fleshed sweet potatoes (a nutrition-sensitive intervention for enhancing domestic intake of vitamin A) in Burundi, Kenya, Rwanda and Uganda. Additionally, milk production increased from 6 to 11 L per cow per day in Uganda and from 6 to 8 L per cow per day in Tanzania, with increases in sales generating USD 115 per cow per month above the non-beneficiaries. These results are supported by previous studies on technology adoption, investments in agriculture and well-being outcomes. Our findings with the higher farm income Difference-in-Differences (DiD) estimator for the female beneficiaries compared to male beneficiaries might have important implications for investing in regional development projects that will close the gender gap in agricultural productivity in Africa. Regional projects can also support post-conflict development efforts for food security and peace in fragile contexts such as in Burundi. Our findings might serve as an input to the African Union's Comprehensive Africa Agriculture Development Programme, localization of the United Nations Sustainable Development Goals related to food security and agriculture in Africa and an input to monitoring, evaluation and learning. 相似文献
29.
A conflict over male production arises in social insects where workers are able to lay unfertilized male eggs. This happens
because each female (queen or worker) is most closely related to her own sons and is thus predicted to reproduce. The conflict
is modulated by worker policing where workers prevent each other from reproducing by aggression or egg cannibalism. In this
study, we show that in the ant Formica fusca, worker policing occurs by egg cannibalism rather than by overt aggression among workers. Furthermore, we show that, contrary
to bees, wasps and other ant species, egg discrimination in F. fusca is not based only on a universal queen signature chemical and that nest mate recognition of eggs occurs. 相似文献
30.
McCann M 《Journal of Safety Research》2003,34(5):507-514
Problem: This study examined deaths of construction workers due to personnel lifts (boom-supported and scissor lifts, suspended scaffolds, and crane platforms). Methods: Deaths of construction workers for 1992–1999 were examined using data from the Census of Fatal Occupational Injuries, a Bureau of Labor Statistics database. Results: The study identified 339 deaths: 42% from boom-supported lifts; 26% from suspended scaffolds; 19% from scissor lifts; 5% from crane platforms; and 7% from unapproved lifts (e.g., forklift platforms). The main causes of death were falls (36%), collapses/tipovers (29%), and electrocutions (21%). Discussion: Recommendations include: following OSHA regulations, wearing personal fall protection equipment, adequate maintenance, inspection before use, and training on the model of lift used. Precautions are also needed to prevent contact with overhead power lines. Impact on industry: The increasing popularity of boom-supported lifts and scissor lifts, both in construction and other industries, make their safety an important issue. 相似文献