Brood Cycle Research Articles

Solar-assisted poultry production in small-scale farms: a case study in the Bekaa semi-arid region, Lebanon

BackgroundIn Lebanon, poultry production is one of the major components of the agricultural sector; however, it suffers from increasing energy costs necessary to cover poultry heating requirements. This affects the profits of brooding farms, namely, small-scale farms in rural areas. Few studies have addressed the use of renewable energy in the poultry industry in Lebanon, with most having focused on modelling ventilation and air quality requirements in poultry houses. Therefore, there is a need to investigate the efficiency of renewable energy sources in providing heating requirements for poultry production. Accordingly, this study evaluates the performance of a solar-assisted, localized heating system in providing heat requirements for chicks in a renovated green poultry house in the Bekaa semi-arid rural region in Lebanon. For this aim, two brooding cycles were conducted during the warm and cold seasons in a greenhouse and were later replicated in a conventional poultry house.ResultsThe energy inputs in the green and conventional houses, respectively, were 33,995.39 and 40,656.97 MJ (1000 birds)−1 in the warm season, and 37,058.25 and 45,770.05 MJ (1000 birds)−1 in the cold season. Calculated energy efficiency values for the green and conventional poultry houses were, respectively, 0.58 and 0.50 in the warm season, and 0.46 and 0.41 in the cold season. The net return was negative for both systems and the benefit-to-cost ratio from broiler production was calculated to be 0.49 and 0.50 in the green and conventional houses, respectively. Life cycle cost analysis showed that adopting the green heating system in the studied farm would entail an 18.89% increase in cost over a period of 20 years as compared to the conventional system.ConclusionIt was concluded that poultry production is not profitable in small-scale farms in the studied area in Lebanon. The use of renewable energy might be more suited for large-scale broiler operations to achieve their purpose in reducing overall production costs. Optimization of the green system to fully satisfy the poultry energy requirements would render it more economically competitive.

Old strategies as modern solutions, shook swarming reduced Varroa destructor infestation rates of managed honey bee, Apis mellifera, colonies

Transferring adult honey bees from the combs of their hive to a new empty hive is a management strategy known as “shook swarming” that has been used by beekeepers in a variety of contexts since as early as 1796. Varroa destructor are dependent on mature brood to reproduce and shook swarming breaks the colony’s brood cycle by separating the adult bees from the brood developing in the old combs. We investigated the efficacy and practicality of shook swarming to mitigate negative health effects of Varroa in honey bee colonies by reducing Varroa infestation rates. New colonies were founded via traditional splitting or the shook swarm technique either with or without comb in the new hive. All colonies were given ∼1 month to establish and then assessed for foraging activity, colony strength, and Varroa infestation rate. We observed a significant decrease in the Varroa infestation rates of colonies that experienced shook swarming compared with those that had not. Colonies established via shook swarming had lower colony strength scores but maintained similar relative foraging activity as traditional splits. Our findings indicate that shook swarming is a viable, non-chemical control strategy for managing Varroa infestations and should be considered in long-term management plans where colonies undergo shook swarming aligned with honey production and/or pollination service delivery.

Toxicity of Coumaphos Residues in Beeswax Foundation to the Honey Bee Brood.

Coumaphos is one of the most frequently detected pesticides in recycled beeswax. The objective was to assess the maximal level of coumaphos in foundation sheets that could exist without lethal effects on the honey bee larvae. Brood development was followed in cells drawn on foundation squares containing coumaphos ranging from 0 to 132 mg/kg. Furthermore, larval exposure was determined by measuring the coumaphos level in the drawn cells. Coumaphos levels in the initial foundation sheets up to 62 mg/kg did not increase brood mortality because the emergence rates of bees raised on these foundation squares were similar to controls (median of 51%). After a single brood cycle, coumaphos levels in the drawn cells were up to three times lower than the initial levels in foundation sheets. Hence, coumaphos levels of 62 mg/kg in the initial foundation sheets, almost the highest exposures, resulted in levels of 21 mg/kg in drawn cells. A significantly reduced emergence rate (median of 14%) was observed for bees raised on foundation sheets with initial coumaphos levels of 132 mg/kg, indicating increased brood mortality. Such levels resulted in coumaphos concentrations of 51 mg/kg in drawn cells, which is close to the median lethal concentration (LC50) as determined in previous in vitro experiments. In conclusion, brood mortality was increased on wax foundation sheets with initial coumaphos levels of 132 mg/kg, while no elevated mortality was observed for levels up to 62 mg/kg. Environ Toxicol Chem 2023;42:1816-1822. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Early Filial Cannibalism in Fish Revisited: Endocrinological Constraint, Costs of Parental Care, and Mating Possibility.

AbstractOffspring desertion by parents generally occurs at an early stage of parental care, which is thought to minimize the costs of parental care prior to desertion. This study investigated the effects of endocrinological constraints on early total filial cannibalism by male Rhabdoblennius nitidus in the field, a paternal brooding blennid fish with androgen-dependent brood cycling. In brood reduction experiments, cannibal males showed low levels of plasma 11-ketotestosterone (11-KT) relative to noncannibals and also similar levels of 11-KT to males in the parental care phase. Since 11-KT regulates male courtship intensity, males with decreased courtship activity would exhibit total filial cannibalism. However, there is a possibility that a transient increase in 11-KT levels at the early stage of parental care delays total filial cannibalism. In contrast, total filial cannibalism could occur before a decline to the lowest 11-KT levels, at which point males might still be able to exhibit courtships, possibly to reduce the costs of parental care. To understand how much and when caregiving males exhibit mating and parental care behaviors, it is important to consider not only the presence of endocrinological constraints but also its intensity and flexibility.

Integrative assessment of immunity, health-state, growth and survival of Magellanic penguin chicks in a colony exposed to ecotourism

Accumulating reports of negative impacts of tourist activities on wildlife emphasize the importance of closely monitoring focal populations. Although some effects are readily noticed, more subtle ones such as changes in physiological functions of individuals might go overlooked. Based on evidence of altered physiology associated with ecotourism on Magellanic penguins Spheniscus magellanicus, here we performed an integrated assessment using a diverse physiological toolkit together with more traditional fitness-related measures to better understand mechanisms and potential consequences. Chicks exposed to tourism showed altered immune parameters and elevated flea prevalence, reinforcing previous findings. Tourism-exposed female, but not male, chicks also showed relatively lower hematocrit and plasma protein levels, providing evidence consistent with a sex-specific response to tourist visitation. Physiological alterations detected in tourism-exposed young chicks (week 1–2) were maintained and the effect on flea infestation increased during the study period (week 4–5 of post-hatch). Despite the effects on physiology, these did not seem to translate into immediate fitness costs. No detectable tourism effects were found on brood sex ratios, chick growth and body condition, and survival until week 5–6 post-hatch. We detected no effects on reproductive output and only a marginal effect on nest survival during incubation despite previous reports of tourism-associated alterations in stress indices of adults. This disconnection could result if the physiological changes are not strong enough to impact fitness, if effects balance each other out, or if changes are part of a copying strategy. Alternatively, the physiological alterations might only show impacts later in the brooding cycle or even after chick emancipation from their parents. Our results suggest that integrative monitoring of potential anthropogenic impacts on wildlife should include evaluation of physiological mechanisms and individual-level responses in populations exposed to human activities.

Effect of thiamethoxam on the survival of brood in Apis mellifera L. colonies placed in mustard fields

Honey bees come under stress if thiamethoxam (a neonicotinoid insecticide) is used on their forage crops. The lethal and sub-lethal effects of this insecticide have largely been documented on foraging bees in comparison to the non-foraging stages especially the immature stages. Hence, the present study, to know the effect of thiamethoxam (25 and 50 g a.i. ha−1) on the brood of Apis mellifera colonies in mustard was conducted. Brood index, compensation index, and brood termination rate were calculated for the brood area (2 sq. inch) selected at two time intervals i.e. at the time of spray (D0) and seven days after that (D7). Brood index for the brood selected at D7 of thiamethoxam applied at 25 g a.i. ha−1 was statistically at par with the untreated control i.e. its value at 21 days (1.00 ± 0.00-4.48 ± 0.04) was statistically at par with the untreated control (1.00 ± 0.00-4.66 ± 0.01). However, in other treatments viz. brood selected at D0 in thiamethoxam applied at 25 g a.i. ha−1 and at D0 and D7 in thiamethoxam applied at 50 g a.i. ha−1, significant brood mortality was recorded at the end of the brood cycle. Compensation indices and brood termination rates also showed similar effects. Overall, it is concluded that thiamethoxam at the recommended dose i.e. 25 g a.i. ha−1 did not affect the brood which was reared 7 days after the application.

Anthropogenic noise alters parental behavior and nestling developmental patterns, but not fledging condition

Abstract Anthropogenic noise is a ubiquitous feature of the American landscape, and is a known stressor for many bird species, leading to negative effects in behavior, physiology, reproduction, and ultimately fitness. While a number of studies have examined how anthropogenic noise affects avian fitness, there are few that simultaneously examine how anthropogenic noise impacts the relationship between parental care behavior and nestling fitness. We conducted Brownian noise playbacks for 6 h a day during the nesting cycle on Eastern Bluebird (Sialia sialis) nest boxes to investigate if experimentally elevated noise affected parental care behavior, nestling body conditions, and nestling stress indices. We documented nest attendance by adult females using radio frequency identification (RFID), and we assessed nestling stress by measuring baseline corticosterone levels and telomere lengths. Based on the RFID data collected during individual brood cycles, adult bluebirds exposed to noise had significantly higher feeding rates earlier in the brood cycle than adults in the control group, but reduced feeding rates later in the cycle. Nestlings exposed to noise had higher body conditions than the control nestlings at 11 days of age, but conditions equalized between treatments by day 14. We found no differences in nestling baseline corticosterone levels or nestling telomere lengths between the two treatment groups. Our results revealed that noise altered adult behavior, which corresponded with altered nestling body condition. However, the absence of indicators of longer-term effects of noise on offspring suggests adult behavior may have been a short-term response.

Chronic High Glyphosate Exposure Delays Individual Worker Bee (Apis mellifera L.) Development under Field Conditions.

Simple SummaryGlyphosate-based herbicides (GBH) can be found worldwide throughout conventional agroecosystems due to their unique and effective mode of action. Their use is generally not considered harmful to honey bees, and, consequently, foragers may encounter food sources that are potentially contaminated with GBH residues. However, recent studies found GBH to cause sublethal effects in bees, and therefore give rise to concern. While most related research has addressed such effects under laboratory conditions, field-realistic approaches under free-flying conditions are scarce. Here, we explore if GBH influences several important performance parameters at the colony level using standard and modified regulatory testing methods. Colony conditions (i.e., colony weight gain, individual worker bee survival, and overwintering) were not affected when subjected to chronic GBH exposure in a realistic range (high and low). In line with previous laboratory results, the high range of treatments revealed a delayed brood development of workers and reduced hatching weight of adults when compared with the control group. However, we concluded that more drastic effects on honey bee health did not seem to appear, as a broad range of performance parameters remained completely unaffected. In future research, the underlying mechanisms of the developmental delay that was confirmed here should be carefully investigated.The ongoing debate about glyphosate-based herbicides (GBH) and their implications for beneficial arthropods gives rise to controversy. This research was carried out to cover possible sublethal GBH effects on the brood and colony development, adult survival, and overwintering success of honey bees (Apis mellifera L.) under field conditions. Residues in bee relevant matrices, such as nectar, pollen, and plants, were additionally measured. To address these questions, we adopted four independent study approaches. For brood effects and survival, we orally exposed mini-hives housed in the “Kieler mating-nuc” system to sublethal concentrations of 4.8 mg glyphosate/kg (T1, low) and 137.6 mg glyphosate/kg (T2, high) over a period of one brood cycle (21 days). Brood development and colony conditions were assessed after a modified OECD method (No. 75). For adult survival, we weighed and labeled freshly emerged workers from control and exposed colonies and introduced them into non-contaminated mini-hives to monitor their life span for 25 consecutive days. The results from these experiments showed a trivial effect of GBH on colony conditions and the survival of individual workers, even though the hatching weight was reduced in T2. The brood termination rate (BTR) in the T2 treatment, however, was more than doubled (49.84%) when compared to the control (22.11%) or T1 (20.69%). This was surprising as T2 colonies gained similar weight and similar numbers of bees per colony compared to the control, indicating an equal performance. Obviously, the brood development in T2 was not “terminated” as expected by the OECD method terminology, but rather “slowed down” for an unknown period of time. In light of these findings, we suggest that chronic high GBH exposure is capable of significantly delaying worker brood development, while no further detrimental effects seem to appear at the colony level. Against this background, we discuss additional results and possible consequences of GBH for honey bee health.

Embryonic development and fecundity of the red deep-sea crab Chaceon quinquedens (Smith, 1879) (Decapoda: Brachyura: Geryonidae) in the Mid-Atlantic Bight determined by image analysis

Abstract The red deep-sea crab, Chaceon quinquedens (Smith, 1879), has been harvested from the US Atlantic continental shelf since the 1970s, but knowledge about its biology is extremely limited. We describe the stages and seasonality of embryonic development and determine size-specific fecundity for C. quinquedens in the Mid-Atlantic Bight. Samples were collected by trawling aboard research vessels in 2012–2013, and from traps aboard commercial fishing vessels in 2014–2016. Four stages of embryonic development were described: 1) early development, 2) mid-development, 3) late development, and 4) hatching. A relationship between embryonic development stage and egg-mass color was observed. A brooding cycle was proposed after analyzing seasonal changes in the stages of embryonic development. Fecundity was estimated by using an automated imaging method for egg samples during stage 1 and 2. The estimates of fecundity, the number of eggs per brood, ranged from 34,691 to 324,729 for females between 62.6 and 106.2 mm in carapace length (CL). The linear regression showed a positive correlation between fecundity and female body size in CL (R2 = 0.56). This study provides information on reproductive parameters needed to improve fisheries management.

The intestinal environment as an evolutionary adaptation to mouthbrooding in the Astatotilapia burtoni cichlid

Many of the various parental care strategies displayed by animals are accompanied by a significant reduction in food intake that imposes a substantial energy trade-off. Mouthbrooding, as seen in several species of fish in which the parent holds the developing eggs and fry in the buccal cavity, represents an extreme example of reduced food intake during parental investment and is accompanied by a range of physiological adaptations. In this study we use 16S sequencing to characterize the gut microbiota of female Astatotilapia burtoni cichlid fish throughout the obligatory phase of self-induced starvation during the brooding cycle in comparison to stage-matched females that have been denied food for the same duration. In addition to a reduction of gut epithelial turnover, we find a dramatic reduction in species diversity in brooding stages that recovers upon release of fry and refeeding that is not seen in females that are simply starved. Based on overall species diversity as well as differential abundance of specific bacterial taxa, we suggest that rather than reflecting a simple deprivation of caloric intake, the gut microbiota is more strongly influenced by physiological changes specific to mouthbrooding including the reduced epithelial turnover and possible production of antimicrobial agents.

Filial Cannibalism by Male Fish as an Infanticide to Restart Courtship by Self-Regulating Androgen Levels

Parental care is costly for animal parents [1-3], who often desert, abort, or kill their offspring and sometimes even eat them-so-called filial cannibalism [1,4]. A primary adaptive hypothesis for filial cannibalism centers on the expected nutritional benefits from eating offspring (the energy-based [EB] hypothesis [5-7]). However, many empirical studies are inconsistent with the EB hypothesis [8, 9]. One notable case is total filial cannibalism observed in some fishes. The caregiving males of these species eat all eggs and restart reproduction when tending a small number of eggs, as predicted by the EB hypothesis; but, this is puzzling because they can potentially court females even while tending eggs and increase the eggs by additional matings. Here we show that brood termination known as total filial cannibalism in blenniid fish Rhabdoblennius nitidus males is an endocrinological necessity to restart courtship behavior for subsequent mating. Males exhibit androgen-dependent brood cycling, and they are normally incapable of exhibiting courtships during the parental phase [10]. Egg manipulation experiments demonstrated that egg presence in the nest is a key stimulus regulating male androgen levels; they cannot restart courtship until removing all eggs. Furthermore, surprisingly, eggs were sometimes spit out without being consumed, and the occurrence of cannibalization and removal of all eggs was not associated with male condition. These results strongly suggest that the egg cannibalistic and removal behaviors that have been regarded as total filial cannibalism in this species are infanticide or embryocide rather than cannibalism, which serve to increase the males' androgen levels.

Living under intertidal mussels: distribution, reproduction, and condition indices in a brooding sea star, Anasterias minuta, in Patagonia, Argentina

Anasterias minuta is an abundant brooding sea star inhabiting tidepool habitats and mussel beds of Perumytilus purpuratus in Patagonia, Argentina. This study explores the influence of mussel bed complexity and tidal height on the size distribution of A. minuta living under mussel beds, and compares the abundance, reproduction, and condition indices in contrasting intertidal microhabitats (mussel hummocks and tidepools). Distribution patterns in mussel beds were explored at four sites along the coast of Argentina (45.4°S–47.4°S) during the austral spring, 2012/2017. Microhabitat comparisons were done at Caleta Cordova Norte between May 2004 and June 2005. Abundance inside mussel beds was correlated positively with mussel bed thickness and presence of mussel hummocks, and negatively with tidal height. Within mussel beds, early juveniles (recruits) and juveniles (greatest radius R < 15 mm) were generally restricted to low-tidal heights, while adults (R ≥ 15 mm) extended to mid-tidal levels. Sea stars were more abundant and larger in tidepools than under mussel beds. Numbers of recruits and juveniles increased significantly under mussel hummocks during austral spring and summer, coinciding with the release and subsequent growth of early juveniles. Brooding and gonadal cycles were synchronized between the microhabitats; however, the brooding cycle was nearly 2 months shorter under mussel hummocks (April–August) than in tidepools (April–October). The sea stars under mussels were smaller, had a less developed body wall, and greater gonadal production, indicating that more energy was allocated to reproduction compared to sea stars of similar size from tidepools. Further studies are needed to identify the specific environmental conditions that led to the observed adaptations and to understand the underlying physiological mechanisms.

Stress indicator gene expression profiles, colony dynamics and tissue development of honey bees exposed to sub-lethal doses of imidacloprid in laboratory and field experiments.

In this study, different context-dependent effects of imidacloprid exposure on the honey bee response were studied. Honey bees were exposed to different concentrations of imidacloprid during a time period of 40 days. Next to these variables, a laboratory-field comparison was conducted. The influence of the chronic exposure on gene expression levels was determined using an in-house developed microarray targeting different immunity-related and detoxification genes to determine stress-related gene expression changes. Increased levels of the detoxification genes encoding, CYP9Q3 and CYT P450, were detected in imidacloprid-exposed honey bees. The different context-dependent effects of imidacloprid exposure on honey bees were confirmed physiologically by decreased hypopharyngeal gland sizes. Honey bees exposed to imidacloprid in laboratory cages showed a general immunosuppression and no detoxification mechanisms were triggered significantly, while honey bees in-field showed a resilient response with an immune stimulation at later time points. However, the treated colonies had a brood and population decline tendency after the first brood cycle in the field. In conclusion, this study highlighted the different context-dependent effects of imidacloprid exposure on the honey bee response. These findings warn for possible pitfalls concerning the generalization of results based on specific experiments with short exposure times. The increased levels of CYT P450 and CYP9Q3 combined with an immune response reaction can be used as markers for bees which are exposed to pesticides in the field.

Temporal and sex-specific patterns of breeding territory defense in a color-polymorphic cichlid fish

In biparental species, the costs and benefits of parental investment can vary between the sexes and shift over time. However, such sex-specific and temporal changes in territory defense are not well understood. Here, we experimentally investigated parental investment in breeding territory defense in a feral population of the color-polymorphic, biparental cichlid fish, the red devil (Amphilophus labiatus). We presented either gold- or dark-colored conspecific intruder models (i.e., dummy models) to A. labiatus pairs at three key stages during the breeding cycle (i.e., after pair formation, after eggs have been laid, and when fry were free-swimming). We found that males were more aggressive when the pair first formed, whereas females significantly increased their territory defense with time, and were most aggressive when fry were free-swimming. These results show that parental roles in territory defense can markedly shift over key stages of the breeding cycle. Our results demonstrate that parental behaviors may not only vary between the sexes, but can also shift dramatically over the course of the brood cycle.

Effects of high pCO2 on Tanner crab reproduction and early life history, Part II: carryover effects on larvae from oogenesis and embryogenesis are stronger than direct effects

AbstractAnthropogenic CO2 release is increasing the pCO2 in the atmosphere and oceans and causing a decrease in the pH of the oceans. This decrease in pH, known as ocean acidification, can have substantial negative effects on marine life. In this study, we use wild-brooded larvae and larvae from females held in treatment pH for two brooding cycles over 2 years to detect carryover effects from oogenesis and embryogenesis. Ovigerous females were held at three pHs: ∼8.1 (Ambient), 7.8, and 7.5. Exposure to acidified conditions at the larval stage alone had minimal effects on the larvae, possibly because larvae may be adapted to living in an environment with large pH swings. Exposure of Tanner crab larvae to low pH during the embryo phase had a more substantial effect on morphology, size, Ca/Mg content, and metabolic rate than exposure during the larval phase, and maternal exposure during the oogenesis phase increased the carryover effect. Although the larval phase itself is resilient to low pH, carryover effects are likely to have a negative effect on larvae in the wild. These results, combined with negative effects of high pCO2 at other life history stages, indicate that high pCO2 may have a negative effect on the Tanner crab populations and fisheries soon.

Honeybee Colony Vibrational Measurements to Highlight the Brood Cycle.

Insect pollination is of great importance to crop production worldwide and honey bees are amongst its chief facilitators. Because of the decline of managed colonies, the use of sensor technology is growing in popularity and it is of interest to develop new methods which can more accurately and less invasively assess honey bee colony status. Our approach is to use accelerometers to measure vibrations in order to provide information on colony activity and development. The accelerometers provide amplitude and frequency information which is recorded every three minutes and analysed for night time only. Vibrational data were validated by comparison to visual inspection data, particularly the brood development. We show a strong correlation between vibrational amplitude data and the brood cycle in the vicinity of the sensor. We have further explored the minimum data that is required, when frequency information is also included, to accurately predict the current point in the brood cycle. Such a technique should enable beekeepers to reduce the frequency with which visual inspections are required, reducing the stress this places on the colony and saving the beekeeper time.

Environmental Implication of Poultry Waste Generation and Management Techniques in Minna, Semi-arid Region of Nigeria

To develop an acceptable manure management and pollution prevention plan in poultry production, accurate accounting of waste generation and concentration of the waste need to be ascertained. In view of this, a study was conducted in Minna, Nigeria to assess quantity of waste generated and the quality of the wastes in selected registered poultry farms. This is with a view to knowing present waste generation status and managements strategies with respect to environmental protection and recommending appropriate management methods to protect air, surface and groundwater environments. Questionnaires focusing on farm information, birds’ information and waste management were administered in the farms. Findings from the questionnaires showed that a total of 2,131,400 layers, 1,224,840 broilers and 848,570 cockerels which amount to a total of 4,204,810 birds are raised annually in confinement in the farms covering an area of 170 hectares of land. From calculation, the farms generate 100.97 metric tons of dead birds over a brooding cycle with about 159,430 metric ton of poultry waste excluding slaughter house litter and hatchery wastes. Management of the waste is poor in the farms visited as indiscriminate dumping on land and burning are major waste management systems in these farms. Only a few adopt re-feed method, dead birds are buried without minding the shallow water table of the area. This waste generation and management method need to be changed to safe Minna environment from imminent hazards. Modern management strategies like green disposal, gasification and biogas production and composting are recommended for Minna poultry farmers because are more environmental friendly and can generate of resources from the waste.

Impact of control strategies for Varroa destructor on colony survival and health in northern and central regions of Italy

SummaryA comparison among four different summer strategies for the control of Varroa destructor was carried out from summer 2010 until spring 2011, in collaboration with national beekeepers associations in Italy. A total of 170 colonies located in Lazio, Piedmont, Tuscany, Veneto were involved. The control strategies included chemical treatments and biotechnical methods (thymol, formic acid, brood removal and brood interruption). In each colony, bee samples were collected before and after treatment to assess the quantity of Varroa destructor and Nosema spp. and the presence of the main honey bee viruses. Colony strength was assessed several times during the trial. The most effective strategies for maintaining low V. destructor infestation levels and higher colony survival in spring in all regions were brood interruption (caging of the queen for the duration of a brood cycle), followed by brood removal. Brood interruption was the only treatment which yielded a decrease in varroa infestation rates (from 4.36 mites/100 bees (5.61 SD) before treatment to 3.24 mites/100 bees (4.0 SD) after treatment, while the highest average overwintering index (ratio of spring vs. autumn bees) and a lower virus prevalence was observed in the brood removal group. Analyses for virus presence showed that in spring 2011 the most prevalent virus was DWV. Quantification of Nosema spp. spores showed that only N. ceranae was present, with regional differences in infection levels.

Alarm calls of the Cyprus Wheatear Oenanthe cypriaca—one for nest defence, one for parent–offspring communication?

Alarm calling has been interpreted from the viewpoint of parental investment and nest defence. Calling should increase with an increasing value of the brood to the caller or with increasing vulnerability of the brood. Parental alarm calling might also be viewed from assessment–management with callers using vocalisations to elicit affective responses in others, e.g. in silencing offspring. I examined parental alarm calling in the Cyprus Wheatear (Oenanthe cypriaca) at different developmental stages. The Cyprus Wheatear produces two alarm calls, but one is emitted only during a short period of the year (type II alarm call). The commoner alarm call (type I alarm call), however, is used year-round. Predation was simulated using consistent approach by human observers. The brood cycle was divided into (I) incubation, (II) nestling, (III) early fledging, and (IV) late fledging. Type I calls increased from phases I to III, and decreased afterwards. Type II calls were absent during incubating and occurred during nestling and early fledging stages. As a conclusion, I suggest that the type I alarm call might be used to alert the mate, deter the predator and signal strength of nest defence, while the type II alarm call is addressed to offspring.

Changes in male courtship intensity and androgen levels during brood cycling in the blenniid fish Rhabdoblennius nitidus

Androgens, for example testosterone, are major hormones that affect male courtship activity, territorial activity, sexual dimorphism, and reproductive tactics; they reach, and are maintained at, a sufficient level to express such sexual traits at the appropriate time for reproductive success. This study examined the effects of androgen levels (testosterone and 11-ketotestosterone) on male brood cycling with two distinct reproductive phases (i.e. court- ship and parental phases) of a paternal brooding blenny Rhabdoblennius nitidus. Our study showed that time spent on courtship behaviour and androgen levels decreased with progress of brood cycling. In addition, time spent on courtship behaviour of males administered cyproterone acetate, an anti-androgen, was shorter than that of control males. These results indicate that the brood cycling is affected by the change in androgen levels. The study also showed that androgen levels decreased after acquisition of the eggs, irrespective of available spawning space in the nests. This result suggests that the presence of eggs themselves may be a trigger for the shift from the courtship phase to parental phase.