Large Food Sources Research Articles

Impacts of Air Pollution on Richness and Abundance of Bird Species in Phnom Penh Urban Habitats

In Cambodia, there has been no study on the effects of air pollution on birds. Accordingly, the purpose of this study aims to assess the species richness and abundance of birds, to understand air quality status and possible sources of air pollution, as well as to investigate the relationship between the variables of air quality (PM2.5, SO2, NO2, and O3), and bird diversity in two different habitats in Phnom Penh. The study was conducted from February 21 to May 21, 2022, at two study sites: 1) the Royal University of Phnom Penh (RUPP) and 2) the Royal University of Agriculture (RUA). Both universities are located in Phnom Penh. The two areas are structured by vegetation which suitable for birds. We used a point count method to observe and record the number and species of birds in both study areas. The study recorded 18,334 observation individuals (counting), arranged in 50 species, 40 genera, 25 families, and 9 orders. At the RUPP, we recorded 11,190 individuals (counting), arranged into 34 species, 29 genera, 21 families, and 7 orders. In the RUA, we recorded 7,144 observation individuals (counting), arranged into 46 species, 38 genera, 25 families, and 9 orders. An observation of human activities can be a source of air pollution, including transportation, stationary sources, urban development, open burning, etc. The air quality parameters at both study sites were still lower than the air pollution standards set by the Royal Government of Cambodia (RGoC). Among air quality variables, only SO2 and O3 affect birds, but to a lesser degree. Factors that affect birds may be due to green areas, including the number of small and large trees, food sources, and human disturbances.

Wins and losses in intergroup conflicts reflect energy balance in red-tailed monkeys.

The energetic costs and benefits of intergroup conflicts over feeding sites are widely hypothesized to be significant, but rarely quantified. In this study, we use short-term measures of energy gain and expenditure to test whether winning an intergroup encounter is associated with greater benefits, and losing with greater costs. We also test an alternative perspective, where groups fight for access to large food sources that are neither depletable nor consistently monopolizable: in this case, a group that has already fed on the resource and is willing to leave first (the loser) is supplanted by a newly arrived group (the winner). We evaluate energy balance and travel distance during and after encounters for six groups of red-tailed monkeys in Kibale National Park, Uganda. We find that winning groups experience substantial energetic benefits, but do so to recoup from earlier deficits. Losing groups, contrary to predictions, experience minimal energetic costs. Winners and losers are predictable based upon their use of the contested resource immediately before the encounter. The short-term payoffs associated with these stressful conflicts compensate for any associated costs and support the perception that between-group contests are an important feature of social life for species that engage in non-lethal conflicts.This article is part of the theme issue ‘Intergroup conflict across taxa’.

Procjena štete od žižaka (Sitophilus granarius L. i Sitophilus zeamais Motsch.) na različitim hibridima kukuruza

Storage pests are pests adapted to living indoors, where their entire life cycle occurs on stored agricultural products. Nowadays, insects within storage facilities are the main problem in the storage process. Storage systems such as silos, warehouses, and containers are perfect habitats for insects that feed on stored food because they are protected from weather extremes, have unrestricted access to large food sources, and can live continuously for long periods of time. The objective of this study was to determine the intensity of damage by granary (Sitophilus granarius L.) and maize (Sitophilus zeamais Motsch.) weevils on field maize and popcorn and their biological potential over 20 weeks of the storage process. During the study, physical properties of maize (weight, hectolitre weight, moisture and sample weight) and changes in population density of weevils were measured. The results showed differential susceptibility of maize hybrids to weevil feeding. No differences were found between weevil species in terms of the damage they caused. Popcorn does not favor weevil feeding, resulting in low grain damage and high mortality rates for both weevil species. In contrast to popcorn, field corn favors both weevil feeding and weevil reproductive potential, ultimately decreasing grain mass and quality and making it unsuitable for human and livestock consumption. More susceptible field maize can be selected for shorter storage time and thus faster delivery to market.

Assessing White Shark (Carcharodon carcharias) Behavior Along Coastal Beaches for Conservation-Focused Shark Mitigation

Many large coastal sharks are vulnerable to population declines, however, conflict with human activities often results in unselective culls. Successfully and non-destructively, addressing human-wildlife conflicts requires understanding of animal behaviour. However, knowledge about white shark (Carcharodon carcharias) behaviour near surf zones, where shark bites usually occur, is still limited. We used drones to obtain high-resolution tracks of 108 white sharks directly off coastal beaches on the east coast of Australia. White sharks ranged from 1.9 to 4.0 m (total length) and typically swam parallel to the beach line at an average speed of 0.82 m s-1 (~ 3.0 km h-1), with behaviour being characteristic of energy conserving motion and foraging. Notably the presence of schools of fish increased mean swim speeds of sharks by 0.33 m s-1 and caused tracks to be more convoluted. White sharks were also observed to swim straighter and faster with time either side of midday, increasing predicted mean swim speeds by 0.11 m s-1 and net travel velocities by 0.25 m s-1. White sharks also displayed inquisitive behaviour towards various potential food and non-food items. We demonstrate that white sharks display largely predictable track trajectories and slow movement speeds along coastal beaches, which has utility in further developing non-destructive shark mitigation strategies. Whilst some of the behaviour observed might support the exploratory bite hypothesis, there is likely an increased risk of a shark bite to bathers during situations where there are large shark-attracting food sources present.

Genomic exaptation enables Lasius niger adaptation to urban environments

BackgroundThe world is rapidly urbanizing, and only a subset of species are able to succeed in stressful city environments. Efficient genome-enabled stress response appears to be a likely prerequisite for urban adaptation. Despite the important role ants play in the ecosytem, only the genomes of ~13 have been sequenced so far. Here, we present the draft genome assembly of the black garden ant Lasius niger – the most successful urban inhabitant of all ants – and we compare it with the genomes of other ant species, including the closely related Camponotus floridanus.ResultsSequences from 272 M Illumina reads were assembled into 41,406 contigs with total length of 245 MB, and N50 of 16,382 bp, similar to other ant genome assemblies enabling comparative genomic analysis. Remarkably, the predicted proteome of L. niger is significantly enriched relative to other ant genomes in terms of abundance of domains involved in nucleic acid binding, DNA repair, and nucleotidyl transferase activity, reflecting transposable element proliferation and a likely genomic response. With respect to environmental stress, we note a proliferation of various detoxification genes, including glutatione-S-transferases and those in the cytochrome P450 families. Notably, the CYP9 family is highly expanded with 19 complete and 21 nearly complete members - over twice as many compared to other ants. This family exhibits the signatures of strong directional selection, with eleven positively selected positions in ligand-binding pockets of enzymes. Gene family contraction was detected for several components of the olfactory system, accompanied by instances of both directional selection and relaxation.ConclusionsOur results suggest that the success of L. niger in urbanized areas may be the result of fortuitous coincidence of several factors, including the expansion of the CYP9 cytochrome family due to coevolution with parasitic fungi, the diversification of DNA repair systems as an answer to proliferation of retroelements, and the reduction of olfactory system and behavioral preadaptations from non-territorial subdominant life strategies found in natural environments. Diversification of cytochromes and DNA repair systems along with reduced odorant communication are the basis of L. niger pollutant resistance and polyphagy, while non-territorial and mobilization strategies allows more efficient exploitation of large but patchy food sources.

Chimpanzees use long-term spatial memory to monitor large fruit trees and remember feeding experiences across seasons

We studied the nature of information that frugivorous foragers take into account to increase their chances of discovering bountiful fruit crops. We recorded the foraging behaviour of five adult female chimpanzees, Pan troglodytes verus , for continuous periods of 4–8 weeks, totalling 275 full days, throughout multiple fruiting seasons in the Tai National Park, Cote d'Ivoire. We found that chimpanzees fed on individual trees that were significantly larger than other available and reproductively mature trees of the same species, especially if their fruit emitted an obvious smell. Trees that were merely checked for edible fruit, but where monitoring could not have been triggered by olfactory or auditory cues because the tree did not carry fruit, were also significantly larger. Most trees were monitored along the way during travel, but 13% were approached in a goal-directed manner (assessed using a ‘change point test’). These approaches were unlikely to have been initiated by visual cues and occurred more often when females foraged solitarily and when trees were large as opposed to small. Our results suggest that goal-directed monitoring is guided by a long-term ‘what–where’ memory of the location of large potential food sources. These findings were confirmed in a quasiexperiment that tested which of 15 876 potential food trees with different crown sizes were approached in a goal-directed manner. Observations on one female who was followed intensively over 3 consecutive years indicated that monitoring probability was highest for trees with which she had become more familiar through frequent previous visits and that had carried more fruit, suggesting that she was able to remember this information across fruiting seasons. Long-term phenological data on individual trees indicated that the interval between successive fruiting seasons, and hence the ‘memory window’ of chimpanzees required for effective monitoring activities, could be up to 3 years.

Socioeconomic Status, Energy Cost, and Nutrient Content of Supermarket Food Purchases

The relative affordability of energy-dense versus nutrient-rich foods may promote socioeconomic disparities in dietary quality and obesity. Although supermarkets are the largest food source in the American diet, the associations between SES and the cost and nutrient content of freely chosen food purchases have not been described. To investigate relationships of SES with the energy cost ($/1000 kcal) and nutrient content of freely chosen supermarket purchases. Supermarket shoppers (n=69) were recruited at a Phoenix AZ supermarket in 2009. The energy cost and nutrient content of participants' purchases were calculated from photographs of food packaging and nutrition labels using dietary analysis software. Data were analyzed in 2010-2011. Two SES indicators, education and household income as a percentage of the federal poverty guideline (FPG), were associated with the energy cost of purchased foods. Adjusting for covariates, the amount spent on 1000 kcal of food was $0.26 greater for every multiple of the FPG, and those with a baccalaureate or postbaccalaureate degree spent an additional $1.05 for every 1000 kcal of food compared to those with no college education. Lower energy cost was associated with higher total fat and less protein, dietary fiber, and vegetables per 1000 kcal purchased. Low-SES supermarket shoppers purchase calories in inexpensive forms that are higher in fat and less nutrient-rich.

Cloning and Characterization of an Armillaria gallica cDNA Encoding Protoilludene Synthase, Which Catalyzes the First Committed Step in the Synthesis of Antimicrobial Melleolides

Melleolides and related fungal sesquiterpenoid aryl esters are antimicrobial and cytotoxic natural products derived from cultures of the Homobasidiomycetes genus Armillaria. The initial step in the biosynthesis of all melleolides involves cyclization of the universal sesquiterpene precursor farnesyl diphosphate to produce protoilludene, a reaction catalyzed by protoilludene synthase. We achieved the partial purification of protoilludene synthase from a mycelial culture of Armillaria gallica and found that 6-protoilludene was its exclusive reaction product. Therefore, a further isomerization reaction is necessary to convert the 6–7 double bond into the 7–8 double bond found in melleolides. We expressed an A. gallica protoilludene synthase cDNA in Escherichia coli, and this also led to the exclusive production of 6-protoilludene. Sequence comparison of the isolated sesquiterpene synthase revealed a distant relationship to other fungal terpene synthases. The isolation of the genomic sequence identified the 6-protoilludene synthase to be present as a single copy gene in the genome of A. gallica, possessing an open reading frame interrupted with eight introns.

Energy Balance During Backpacking

PURPOSE: The energy expenditure (EE) of backpacking has been described in only a few studies, and energy balance has never been reported. This study sought to evaluate EE and energy intake (EI) during an extended backpacking trip. METHODS: Three experienced, aerobically fit backpackers (32-yr old female, 57 ml.min-1.kg-1 VO2max; 34-yr old male, 73 ml.min-1.kg-1; 53-yr old male, 62 ml.min-1.kg-1) recorded their heart rate (HR) and food consumption during a five-day, 162-km trip on a rugged section of the Appalachian Trail. Body mass was recorded shortly before the trip began and immediately upon exiting the trail on day five, using the same scale. Resting EE was estimated as 1 kcal/hr per kg. Exercise EE was estimated two ways: (1) ACSM equation for walking, using distance traveled and gross elevation gained; EE of descents was considered equivalent to flat walking in accordance with past research showing that shallow downhill grades require less EE than flat walking, but steep downhill grades require more than flat walking; (2) the HR/VO2 relationship during treadmill testing was applied to average HR values for each subject for each day during walking. RESUITS: Gross EE using the ACSM equation averaged 4062 kcal on four full days, and 2733 kcal on the fifth day. Gross EE using HR/VO2 was 23% greater. EI averaged 2134 kcal on four full days, and 1117 kcal on the fifth day. The largest food source was snack bars and trail mix, which accounted for 62% of EI. Substrates were 52% carbohydrates, 17% protein and 31 % fat. Average HR during hiking was 105 bpm, or 37% of heart rate reserve. Expected average weight loss was 1.2 kg based on the ACSM walking equation and 1.8 kg based on HR/VO2. Actual weight loss averaged 1.7 kg. CONCLUSIONS: Subjects in this study did not maintain weight during extended backpacking. Their weight loss was more accurately predicted by estimating EE from HR/VO2 than from a walking equation.

Colony structure and foraging behavior in the tropical formicine ant, Gigantiops destructor

We present field and laboratory data on the Neotropical formicine ant Gigantiops destructor (Fabricius), the sole species of its genus and tribe. Monogynous and polydomous colonies of G. destructor from French Guiana are distributed along the rainforest edges or along streams with a nest density of about 300 nests/ha. The species presents rudimentary nesting habits, as most nests are found in pre-existing cavities in the ground, but some can be found in the hollowed internodes of Cecropia trees fallen onto the ground. A worker, sometimes hidden in a separate "sentry box", might guard the nest entrance. Colony size can reach several hundreds of workers. The foraging activity of the workers is strictly diurnal with a peak between 9:30 and 11:30. This largest-eyed of all known ant species has remarkable leaping abilities even more impressive than in other jumping ants. Workers are generalist solitary foragers. They collect extra-floral nectar from different plant species and prey on various small live arthropods that they detect visually before tracking and jumping on them. The same individual can forage both on prey and sugary sources during a single foraging trip. Foragers can eat their prey on site and never recruit nestmates in the field or even after a starvation period in the laboratory. They feed larvae with chewed prey. The complete lack of cooperation between foraging workers that can also fight for a prey with a nestmate, combined with the absence of any recruitment for large food sources, constitute a cluster of individualist traits rather unusual for an eusocial insect.

Individual flexibility and choice of foraging strategy in Polyrhachis laboriosa F. Smith (Hymenoptera, Formicidae)

We report in this study that the tree-dwelling African ant Polyrhachis laboriosa (Formicinae) uses different foraging strategies according to the size of the available food sources. We demonstrate that a recruitment behaviour can be induced with a 125 μl alimentary reward and that foraging remains solitary when rewards are smaller. Small rewards do not elicit trail-laying behaviour, and exploration behaviour is considerable. With large permanent food sources, scouts use group recruitment and there is less exploration around the reward. The choice of the foraging strategy is determined by the first forager, which modifies its behaviour according to the volume of the food supply. Independently of the size of the reward, the forager shows many exploratory displays during the first visit to the source, and contrary to most ants, it never lays a trail during its first return to the nest. Visual cues remain mainly used for individual orientation; information collected during the first trips are then transmitted to nestmates thanks to temporary trail laying behaviour.

Philopatry, male presence and grooming reciprocation among female primates: a comparative perspective

Competition for food and a safe location in a group are considered to be the main determinants of variation in social relationships among female primates. The effect of the presence of males is usually overlooked, however. Here we put forward two hypotheses connecting the (relative) number of males in a group, a statistic measuring the strength of positive relationships among females (the degree of reciprocity of grooming) and female residence. Under the first hypothesis, we assumed that philopatric females suffer especially from competition for males. Because females of these species are restrained to their native group and thus do not move to groups where better conditions (i.e. more males) prevail, a higher socionomic sex ratio would imply reduced competition and this should be reflected in better relationships among females (i.e. in a higher degree of reciprocation). The second hypothesis is based on the contention of Wrangham (1987) that groups with more males are better able to defend large food sources: in these groups female relationships would suffer less from within-group competition for food. We therefore also expected a positive correlation between the absolute number of males and grooming reciprocation. To test the hypotheses, matrices of grooming interactions were collected by going through the primatological literature. For ten female-resident and four female-transfer primate species, the degree of grooming reciprocation was quantified using a specially adapted matrix statistic. The results favoured the first (competition for males) hypothesis. The degree of grooming reciprocation among females was positively correlated with socionomic sex ratio, but neither with group size nor with the absolute number of males. Correlations between the degree of reciprocity and sex ratio were confirmed at three levels: within the same group at different points in time, between groups of the same species, and between species. In addition, the degree of reciprocation increased with sex ratio more strongly in typical single/variable male than in multi-male species. This we interpreted as a direct consequence of the lower social availability of males for females in multi-male groups than single-male groups. In turn, this effect may be due to males competing for females in multi-male groups.

Ritualised versus aggressive behaviours displayed by Polyrhachis laboriosa (F. Smith) during intraspecific competition

The intraspecific territoriality of Polyrhachis laboriosa was studied thanks to dyadic confrontations between nestmates and alien foragers in chemically marked and unmarked arenas, complementing experiments and observations in nature. When foragers meet, the alien flees while the resident attacks, especially when on a marked area. However, when an alien scout extends its territory, it attacks the resident ant, such confrontation resulting in a high rate of reciprocal full attacks. When surrounded by several residents, the intruder is always spread-eagled if it does not succeed in fleeing. We described ritualised displays, such as threatening (opening mandibles; bending the gaster) or appeasing behaviours (antennal boxing; attempt at trophallaxis; pupal posture; raising the gaster). They occur only when the encounter maintains a low level of aggression, during laboratory experiments, or in nature during encounters involving a queen or an experimentally-introduced intruder. Foraging queens are tolerated on the territories of conspecific mature colonies. When they encounter resident workers, reciprocal avoidance occurs. Nevertheless, the latter perform ritualised displays when the queens approach their nest or attempt to rob their prey. This situation seems to compensate in part the archaic semi-claustral mode of foundation of this species, as the queens are indirectly protected by their conspecifics who do not tolerate other competitors around large food sources.

Explosive food recruitment as a competitive strategy in the ant Myrmica sabuleti (Hymenoptera, Formicidae)

Myrmica sabuleti forms mature colonies of about one thousand workers and a few queens. Although living in dry and sunny biotopes, this species avoids foraging during the warmer hours of the day which correspond to the period of the maximum foraging activity of two sympatric species, Formica fusca and F. cunicularia. M. sabuleti is the most frequently observed species on the extrafloral nectaries of Vicia sativa, even during the warmer hours of the day, whereas F. fusca is the most frequent species during those hours at tubes of 1M sucrose solutions placed on the ground. In spite of this temporal segregation, the foraging activity of M. sabuleti and F. fusca overlaps two times a day (10:00‐11:00 am and 5:00‐8:00 pm). Newly discovered large food sources are exploited by M. sabuleti through an explosively increasing recruitment, whereas workers of F. fusca forage mainly individually. Interference between M. sabuleti and F. fusca was studied when offering sucrose solutions, large dead insects unretrievable by individual foragers of either species (cockroaches), medium-sized insects retrievable by single foragers of F. fusca but not by single M. sabuleti(larvae of Calliphora erythrocephala) and small insects (Drosophila) retrievable by individual foragers of both species. Owing to its rapid recruitment, M. sabuleti is able to displace F. fusca from sucrose solution and large dead prey during the overlaping of the activity cycles of both species. When medium-sized corpses are offered, the issue depends on the speed of the events. F. fusca is able to take the prey away only if it discovers it before M. sabuleti has recruited nestmates. Small dead prey do not lead to interference, but is taken by the first worker that finds it.

Ritualized behavior during competition for food between two formicinae

Polyrhachis laboriosa andCamponotus brutus are two syntopic ants of the African equatorial forest. Although they occupy two different ecological niches (nesting area, diet, rhythms of activity), they are in competition for the exploitation of large permanent food sources.

On foraging, recruitment systems and optimum number of scouts in eusocial colonies

A numerical model of an eusocial colony foraging for food showed that, for each set of values of resource density, resource size and recruitment system employed, a given optimal proportion of scouts in the colony maximize the amount of resources retrieved by a colony during a fixed period. The model predicts that ants using mass recruitment systems should have larger colonies with small foragers, and should forage on large food sources. Retrieval of small food sources by small colonies is best achieved with large workers using individual foraging strategies. For mass foragers, several food sources are best retrieved using democratic decision-making systems in recruitment, whereas for very large food sources at very low mean food patch density, autocratic decision-making systems are optimal. Some of the experimental evidence available is discussed in the light of these findings, as they confirm the prediction that large colonies with small workers have mass recruitment systems, whereas workers of small colonies with large workers are generally lone foragers.

Etude de la récolte de nourriture par la fourmi polymorphePheidole pallidula dans son milieu naturel

The dimorphic ant specicsP. pallidula is widespread in all Mediterranean countries and was the dominant species in our study area. Demographic data such as relative abundance, density, spatial distribution were collected and quantitative observations ofP. pallidula behaviour were made at the time of food exploitation. This allowed us to discern the relations, particularly competitives ones, between their workers and other sympatric ant species (Aphaenogaster senilis, Crematogaster sordidula, Messor barbara, Plagiolepis pygmaea). The ecological success ofP. pallidula seems to depend on 3 main characteristics of its ethology: 1o) its foraging activity both diurnal and nocturnal, 2o) the diversity of its foraging techniques (individual and collective retrievals by minor foragers; short and long lasting foraging trails). 3o) the active participation of majors in intense exploitation of large unretrievable food sources where they could be very efficient to protect food sources from competitors and/or to cut preys' sclcrites. These majors are mainly present on food sources and on trails, exploration of the foraging area being ensured by the minor caste. The adaptive significance of caste polyethism ofP. pallidula species during food exploitation is discussed according to our field data.

Feeding rhythms and food of Penaeus japonicus bate (crustacea, penaeidae) in salt marsh ponds; role of halophilic entomofauna

The feeding habits of Penaeus japonicus in aestival, semi-extensive cultivation, were studied in salt marsh ponds of the French Atlantic Coast. A bi-monthly sampling programme was carried out over 3 months: on each occasion, samples were taken hourly over a 24-h period and the stomach contents of a total of 1191 shrimps were analysed. A shift from continuous to nocturnal feeding occurred during the second month of the rearing period (i.e. between 74 and 97 days after metamorphosis). In semi-extensive shrimp culture (from 10 shrimps m −2 at the beginning to 3.4 shrimps m −2 at harvesting), naturally occurring prey were the largest food source throughout the study, despite a daily supply of pellet food. Shrimps appeared to be opportunistic carnivores since they fed on all the salt marsh fauna, with a preference for halophilic insects, especially chironomids. However, a selection of prey, related to their size, was observed over the rearing period. The choice of prey shifted in the following order: zooplankton and harpacticoids (Day 0-Day 7) — harpacticoids (D 7-D 27) — chironomids (D 27-D 62) — macrobenthos and chironomids (D 62-D 86). Feeding rhythms and food preferences are discussed in relation to data obtained in similar studies.

Response of Pheidole morrisi to two species of enemy ants, and a general model of defense behavior in Pheidole (Hymenoptera: Formicidae).

Response of Pheidole morrisi to two species of enemy ants, and a general model of defense behavior in Pheidole (Hymenoptera: Formicidae).

Error, communication and learning in ant societies

When large food sources are discovered, many species recruit using different mechanisms. Numerous recruits do not reach the food source and explore the foraging area. These ants make new discoveries. The interplay between communication and exploration generates collective and efficient structures. This organisation is discussed in relation to the mechanisms of recruitment, quality and degree of aggregation of food-sources and territorial marking. This first organization, characteristic of large colonies, is compared to another foraging organisation: small societies of deterministic and specialised foragers rarely communicating together.