Patch exploitation in a producer-scrounger system: test of a hypothesis using flocks of spice finches (Lonchura punctulata)

Group foraging allows individuals (scroungers) to obtain fooddiscovered by others (producers). Producer-scrounger game modelstypically overlook the costs and benefits of patch exploitation,assuming instead that producers and scroungers abandon patchessimultaneously once depletion occurs. Here we develop an extensionof the marginal value theorem of patch exploitation that includesthe producer-scrounger dynamics and examine the propensity ofa producer to abandon its patch before depletion once scroungersarrive. We predict that early departures should occur more oftenwhen expected searching time decreases and when competitionintensity in the patch increases. Competition intensity is expectedto increase when more scroungers are present or when patchesare smaller. We tested these predictions using a within-subjectexperimental design with six captive flocks of spice finches(Lonchura punctulata), each composed of one producer and threescroungers. As predicted, producers abandoned their food discoveriesmore frequently once scroungers arrived when searching timewas short, when more scroungers were present, and when patcheswere small. The results show that the producers of a patch oftenleave as scroungers join their food discoveries because thepayoffs from leaving exceed those from staying     

An asymmetric producer-scrounger game: body size and the social foraging behavior of coho salmon

A tension between cooperation and conflict characterizes the behavioral dynamics of many social species. The foraging benefits of group living include increased efficiency and reduced need for vigilance, but social foraging can also encourage theft of captured prey from conspecifics. The payoffs of stealing prey from others (scrounging) versus capturing prey (producing) may depend not only on the frequency of each foraging strategy in the group but also on an individual’s ability to steal. By observing the foraging behavior of juvenile coho salmon (Oncorhynchus kisutch), we found that, within a group, relatively smaller coho acted primarily as producers and took longer to handle prey, and were therefore more likely to be targeted by scroungers than relatively larger coho. Further, our observations suggest that the frequency of scrounging may be higher when groups contained individuals of different sizes. Based on these observations, we developed a model of phenotype-limited producer-scrounger dynamics, in which rates of stealing were structured by the relative size of producers and scroungers within the foraging group. Model simulations show that when the success of stealing is positively related to body size, relatively large predators should tend to be scroungers while smaller predators should be producers. Contrary to previous models, we also found that, under certain conditions, producer and scrounger strategies could coexist for both large and small phenotypes. Large scroungers tended to receive the highest payoff, suggesting that producer-scrounger dynamics may result in an uneven distribution of benefits among group members that—under the right conditions—could entrench social positions of dominance.     

Geometry for a selfish foraging group: a genetic algorithm approach

The advantages of group living are not shared equally among all group members and these advantages may depend on the spatial position occupied by a forager within the group. For instance, it is thought that socially dominant individuals prefer the predator-safe central position of groups forcing subordinates to the periphery. Uneven spread of benefits among group members can occur when some animals (the scroungers) parasitically exploit the food findings of other foragers (the producers). Here we focus on how playing producer or scrounger affects an individual''s spatial position within a group. We model the movement of foraging animals playing scrounger or producer using a spatially explicit simulation and use a genetic algorithm to establish movement rules. We find that groups containing producers and scroungers are more compact compared to an equivalent group of producers only. Furthermore, the position occupied by strategies varies: scroungers are mainly found in central positions, while producers in the periphery, suggesting that the best position for strategies differs. Dominants, therefore, should prefer movement rules which lead to central positions because of the positional benefits provided to the scrounger strategy they use. Moreover, position within a group will introduce an asymmetry among otherwise phenotypically symmetric individuals.     

The patch distributed producer-scrounger game

Grouping in animals is ubiquitous and thought to provide group members antipredatory advantages and foraging efficiency. However, parasitic foraging strategy often emerges in a group. The optimal parasitic policy has given rise to the producer-scrounger (PS) game model, in which producers search for food patches, and scroungers parasitize the discovered patches. The N-persons PS game model constructed by Vickery et al. (1991. Producers, scroungers, and group foraging. American Naturalist 137, 847-863) predicts the evolutionarily stable strategy (ESS) of frequency of producers that depends on the advantage of producers and the number of foragers in a group. However, the model assumes that the number of discovered patches in one time unit never exceeds one. In reality, multiple patches could be found in one time unit. In the present study, we relax this assumption and assumed that the number of discovered patches depends on the producers’ variable encounter rate with patches (λ). We show that strongly depends on λ within a feasible range, although it still depends on the advantage of producer and the number of foragers in a group. The basic idea of PS game is the same as the information sharing (parasitism), because scroungers are also thought to parasitize informations of locations of food patches. Horn (1968) indicated the role of information-parasitism in animal aggregation (Horn, H.S., 1968. The adaptive significance of colonial nesting in the Brewer's blackbird (euphagus cyanocephalus). Ecology 49, 682-646). Our modified PS game model shows the same prediction as the Horn's graphical animal aggregation model; the proportion of scroungers will increase or animals should adopt colonial foraging when resource is spatiotemporally clumped, but scroungers will decrease or animals should adopt territorial foraging if the resource is evenly distributed.     

Producer–Scrounger Games in a Spatially Explicit World: Tactic Use Influences Flock Geometry of Spice Finches

Group-foraging animals can either search for their food (producer) or search for opportunities to join the food discoveries of others (scrounger). To maximize food returns, producers should distance themselves from potential competitors whereas scroungers should increase proximity to potential producers. We investigated the extent to which playing one or the other tactic affected an individual's location in captive flocks of ground-feeding spice finches ( Lonchura punctulata ) as they foraged for hidden clumps of food on an aviary floor. We constrained some individuals to use the producer tactic by pre-training them to find food hidden under lids. Constrained producers foraged significantly further from the center of flocks than constrained scroungers. Flocks with many scroungers were significantly more compact than flocks with fewer scroungers. The results are consistent with published simulations of spatially explicit producer–scrounger models and suggest that the use of producer and scrounger foraging tactics be included as a factor that affects an individual's position within foraging groups.     

Producing and scrounging can have stabilizing effects at multiple levels of organization

This study shows, for the first time, that the evolution of a simple behavior, scrounging, at the individual level can have effects on populations, food chains, and community structure. In particular, the addition of scrounging in consumer populations can allow multiple consumers to coexist while exploiting a single prey. Also, scrounging in the top predator of a tritrophic food chain can stabilize interactions between the top predator, its prey, and its prey's prey. This occurs because the payoffs to scrounging for food in a population are negative frequency dependent, allowing scroungers to invade a population and to coexist with producers at a frequency which is density‐dependent. The presence of scroungers, who do not search for resources but simply use those found by others (producers) reduces the total amount of resource acquired by the group. As scrounging increases with group size, this leads to less resource acquired per individual as the group grows. Ultimately, this limits the size of the group, its impact on its prey, and its ability to outcompete other species. These effects can promote stability and thus increase species diversity. I will further suggest that prey may alter their spatial distribution such that scrounging will be profitable among their predators thus reducing predation rate on the prey.     

The Payoffs to Producing and Scrounging: What Happens when Patches are Divisible?

Although many group-foraging models assume that all individuals search for and share their food equally, most documented instances of group foraging exhibit specialized use of producer and scrounger strategies. In addition, many of the studies have focused on groups with strong individual asymmetries exploiting food that is not easily divisible. In the present study we describe individual foraging behavior of relatively nonaggressive flock foragers exploiting divisible clumps of food. Two experiments, one with flocks of spice finches and another with flocks of zebra finches, suggest that divisibility of food patches may have important consequences for social foraging behavior. Neither dominance nor the distribution and quality of food patches affect the relative advantage that producing individuals enjoy over those that scrounge. Specialized producers and scroungers are absent from flocks of both species. Systems where patches are shared may differ fundamentally from those where patches are monopolized by scroungers.     

Consequences of multiple simultaneous opportunities to exploit others’ efforts on free riding

Individuals within a group do not all act in the same way: Typically, the investors (or producers) put efforts into producing resources while the free riders (or scroungers) benefit from these resources without contributing. In behavioral ecology, the prevalence of free riders can be predicted by a well‐known game‐theoretical model—the producer–scrounger (PS) model—where group members have the options to either search for resources (producers) or exploit the efforts of others (scroungers). The PS model has received some empirical support, but its predictions, surprisingly, are based on the strict assumption that only one resource can be exploited at a time. Yet, multiple simultaneous opportunities to exploit others’ efforts should frequently occur in nature. Here, we combine analytic and simulation approaches to explore the effect of multiple simultaneous scrounging opportunities on tactic use. Our analyses demonstrate that scrounging rates should increase with the number of simultaneous opportunities. As such, the amount and spatial distribution (i.e., clumped vs. dispersed) of resources as well as the risk of predation are key predictors of scrounging behavior. Because scroungers contribute to reducing the speed of resource exploitation, the model proposed here has direct relevance to the exploitation and sustainability of renewable resources.     

The digestive tract and life history of small mammals

The type of food, differentiation of the large intestine and stomach, and methane production, as well as life history data, are considered in Insectivora, Rodentia and Lagomorpha. When food containing plant cell wall material is eaten, there is either a differentiation of the stomach or the large intestine. In animals with low body mass and little differentiation of the gastrointestinal tract, methane production is low, but structures essential for microbial digestion of plant cell wall material, such as haustration of the colon or formation of a caecum, can be found in many methane‐producers. Animals with a body mass < 500 g and a weaning time < 20 days are non‐producers of methane. Establishment of a balanced microbial population in the gastrointestinal tract requires some time. Many non‐producers of methane wean their young in < 10 days, but many producers need > 50 days for the weaning process. Caviomorpha, Thryonomyidae and Hystricidae seem to have ‘opened the door’ to the use of low quality food by microbial fermentation, but some of them have to ‘pay’ for this extension of the food range by an extended weaning period, which also means an extended dependency on the mother.     

Wild Carib grackles play a producer scrounger game

Producer–scrounger (PS) game-theoretical foraging modelsmake predictions about the decision of group-feeding animalseither to look for food (produce) or for opportunities to exploitthe discoveries of other foragers (scrounge). We report themost complete demonstration to date of the applicability ofthe PS foraging game in a free-living animal, the Carib grackle(Quiscalus lugubris) of Barbados. As assumed by PS games, thepayoffs obtained by scroungers were negatively frequency dependent.Experimentally, increasing the cost of scrounging led to a decreasein the observed proportion of scroungers, whereas raising thecost of producing increased the proportion of scroungers. Observationsof marked birds revealed that group-level changes could be broughtabout by individual flexibility in tactic use. Despite consistentindividual differences in tactic use, most birds used both tacticsand could alter their use of producing and scrounging when conditionschanged. We found no difference in the payoffs obtained by producersand scroungers, suggesting a symmetrical game equilibrium. Ourresults call for testing the PS foraging game in a broader rangeof biological systems that include different types of scroungingbehavior (e.g., scramble, stealthful, or aggressive scrounging)as well as the exploitation of different phases of food production(e.g., searching, handling).     

What Can Interaction Webs Tell Us About Species Roles?

The group model is a useful tool to understand broad-scale patterns of interaction in a network, but it has previously been limited in use to food webs, which contain only predator-prey interactions. Natural populations interact with each other in a variety of ways and, although most published ecological networks only include information about a single interaction type (e.g., feeding, pollination), ecologists are beginning to consider networks which combine multiple interaction types. Here we extend the group model to signed directed networks such as ecological interaction webs. As a specific application of this method, we examine the effects of including or excluding specific interaction types on our understanding of species roles in ecological networks. We consider all three currently available interaction webs, two of which are extended plant-mutualist networks with herbivores and parasitoids added, and one of which is an extended intertidal food web with interactions of all possible sign structures (+/+, -/0, etc.). Species in the extended food web grouped similarly with all interactions, only trophic links, and only nontrophic links. However, removing mutualism or herbivory had a much larger effect in the extended plant-pollinator webs. Species removal even affected groups that were not directly connected to those that were removed, as we found by excluding a small number of parasitoids. These results suggest that including additional species in the network provides far more information than additional interactions for this aspect of network structure. Our methods provide a useful framework for simplifying networks to their essential structure, allowing us to identify generalities in network structure and better understand the roles species play in their communities.     

Coevolution of adaptive technology,maladaptive culture and population size in a producer–scrounger game

Technology (i.e. tools, methods of cultivation and domestication, systems of construction and appropriation, machines) has increased the vital rates of humans, and is one of the defining features of the transition from Malthusian ecological stagnation to a potentially perpetual rising population growth. Maladaptations, on the other hand, encompass behaviours, customs and practices that decrease the vital rates of individuals. Technology and maladaptations are part of the total stock of culture carried by the individuals in a population. Here, we develop a quantitative model for the coevolution of cumulative adaptive technology and maladaptive culture in a ‘producer–scrounger’ game, which can also usefully be interpreted as an ‘individual–social’ learner interaction. Producers (individual learners) are assumed to invent new adaptations and maladaptations by trial-and-error learning, insight or deduction, and they pay the cost of innovation. Scroungers (social learners) are assumed to copy or imitate (cultural transmission) both the adaptations and maladaptations generated by producers. We show that the coevolutionary dynamics of producers and scroungers in the presence of cultural transmission can have a variety of effects on population carrying capacity. From stable polymorphism, where scroungers bring an advantage to the population (increase in carrying capacity), to periodic cycling, where scroungers decrease carrying capacity, we find that selection-driven cultural innovation and transmission may send a population on the path of indefinite growth or to extinction.     

Linking the green and brown worlds through nonconsumptive predator effects

Predators can indirectly affect lower trophic levels by either consuming their prey (consumptive effect, CE) or by changing the physiology or behavior of their prey (nonconsumptive effect, NCE). Cascading effects of predators on primary producers are common, and can be propagated by CEs, NCEs, or a combination of both mechanisms. Predator impacts in detrital food webs (the ‘brown world’) have received considerably less attention than their effects on systems with primary producers at the base (the ‘green world’), and only recently have we begun to appreciate the importance of above‐ground predators indirectly impacting below‐ground processes. Numerous studies reveal the total impact (CEs and NCEs) of predators in brown food webs, but our understanding of the role of isolated NCEs is limited. Many habitats and major taxa have not been studied, and patterns are difficult to distinguish due to frequent reporting of mixed effects. Predators play an important role as connectors between brown and green worlds when they feed from both food webs (multichannel feeding). We are only beginning to understand how NCEs influence detrital food webs, and it is unknown whether multichannel fear is an essential component of predator–prey ecology that regulates ecosystem function. Synthesis Predators have been shown to impact ecosystems through both consumptive and nonconsumptive effects on their prey Historically, herbivory‐based ‘green’ systems have been the venue for documenting these predator effects, while detritus‐based ‘brown’ systems received considerably less attention. However, similar mechanisms exist in green and brown worlds, suggesting strong parallels. We review and synthesize predator effects in detrital systems, highlighting important shortcomings in current understanding. Furthermore, we build upon the idea of multichannel feeding (i.e. consumption of prey from both green and brown food webs) to propose the existence of ‘multichannel fear’. We provide a framework for documenting multichannel fear to facilitate continued exploration of how predators link seemingly disparate systems.     

Vultures acquire information on carcass location from scavenging eagles

Vultures are recognized as the scroungers of the natural world, owing to their ecological role as obligate scavengers. While it is well known that vultures use intraspecific social information as they forage, the possibility of inter-guild social information transfer and the resulting multi-species social dilemmas has not been explored. Here, we use data on arrival times at carcasses to show that such social information transfer occurs, with raptors acting as producers of information and vultures acting as scroungers of information. We develop a game-theoretic model to show that competitive asymmetry, whereby vultures dominate raptors at carcasses, predicts this evolutionary outcome. We support this theoretical prediction using empirical data from competitive interactions at carcasses. Finally, we use an individual-based model to show that these producer–scrounger dynamics lead to vultures being vulnerable to declines in raptor populations. Our results show that social information transfer can lead to important non-trophic interactions among species and highlight important potential links among social evolution, community ecology and conservation biology. With vulture populations suffering global declines, our study underscores the importance of ecosystem-based management for these endangered keystone species.     

Multiple interactions networks: towards more realistic descriptions of the web of life

Ecological communities are defined by species interacting dynamically in a given location at a given time, and can be conveniently represented as networks of interactions. Pairwise interactions can be ascribed to one of five main types, depending on their outcome for the species involved: amensalism, antagonism (including predation, parasitism and disease), commensalism, competition or mutualism. While most studies have dealt so far with networks involving one single type of interaction at a time, often focusing on a specific clade and/or guild, recent studies are being developed that consider networks with more than one interaction type and across several levels of biological organisation. We review these developments and suggest that three main frameworks are in use to investigate the properties of multiple interactions networks: ‘expanded food‐webs’, ‘multilayer networks’ and ‘equal footing networks’. They differ on how interactions are classified and implemented in mathematical models, and on whether the effect of different interaction types is expressed in the same units. We analyse the mathematical and ecological assumptions of these three approaches, and identify some of the questions that can be addressed with each one of them. Since the overwhelming majority of studies on multiple interactions are theoretical and use artificially generated data, we also provide recommendations for the incorporation of field data in such studies.     

L'adaptation à la vie arboricole chez les fourmis

Arboreal ants constitute one of the largest animal groups in the tropical forest canopy not just in terms of their individual number and overall biomass, but also in terms of diversity. Because the arboreal habitat has particular characteristics which clearly differentiate it from the ground, the ants' ecological success depends on developing adaptations designed to overcome the constraints peculiar to this environment in order to best exploit its resources. Although it is not always possible to identify all of the characteristics common to all arboreal ants species, those species said to be ‘dominant’ share morphological, physiological and behavioural traits which differentiate them from other ants. The most important difference is the type of food sources exploited. These dominant species feed principally on the nectar of the extra-floral nectaries of plants or on the honeydew of Homoptera. These products are extremely rich in sugary substances and low in nitrogen. The exploitation of these food sources has, then, repercussions on the growth and reproduction of ant colonies, given the importance of nitrogen as a limiting factor. Obtaining the necessary amount of nitrogen involves exploiting large volumes of liquid. From a purely morphological point of view, it is interesting to note that the digestive system of most of the dominant ant species has a modified proventriculus and a thin cuticle which means less need for proteins. These modifications permit individual foragers to transport large volumes of liquid by holding them in their crops in order to distribute them to the rest of the colony. The venom of many of these species also differs from that of other ants in that it lacks nitrogen. Dominant species have, thus, developed adaptations related to their feeding habits, lowering the need for nitrogen in individuals and, in this way, permitting the greater development of the colony. The exploitation of this type of food source is also facilitated by the type of nests constructed by the ants. Indeed, the elaboration of a nest independently of any structure provided by the plant offers numerous advantages, despite the important energetic costs involved. These types of nests allow the ant to (1) ‘choose’ the nest site and thus to install the nest on plants providing the best resources (extra-floral nectaries or Homoptera attendance) and (2) exploit a greater number of resources with lower energy costs by placing parts of the colonies near food sources. In addition, even if part of the sugary food substances are destined for the synthesis of molecules necessary to the survival and proper functioning of individuals, there is a large surplus. This surplus might indirectly reinforce these species' defensive systems on both an inter- as well as intraspecific level by serving as an energy source enabling individuals to have high level of activity and aggressiveness. The remaining arboreal species, which — in terms of diversity — make up the majority, do not share common traits which permit them to be clearly differentiated from terricolous species. Nevertheless, comparisons conducted within a genus show that certain arboreal species have developed adaptations to their way of life, and not only those species living in the domatia of ant plants, but also other, strictly arboreal species. As is the case for dominant species, the modifications observed originate especially in response to the two principal limiting factors in the arboreal habitat: available food resources and a limited number of nest sites.     

Brood division in robins

Broods of fledgling robins Erithacus rubecula are sometimes divided between their parents so that each parent feeds only some of the chicks. These associations between a parent and certain of its young (‘family units’) are shown to be stable over periods of days. Brood division is most frequent in broods that are not followed by another nesting attempt. Experimental manipulation of the food supply suggests that brood division is relaxed when food is readily available. An analysis of the interactions between parents and chicks demonstrates that both adults and fledglings play a role in brood division. The possible functions of brood division are discussed with reference to ‘other types of care’, ‘parental efficiency’, ‘cheat countermeasure’ and ‘two types of chick’ hypotheses. Male parents feed chicks with shorter winglengths than do females: since females tend to have shorter winglengths than males, this suggests that chicks are cared for by parents of the opposite sex. Possible causes and consequences of this observation are discussed.     

Fish diet composition in floodplain lagoons of an Australian dryland river in relation to an extended dry period following flooding

Floodplain rivers worldwide are threatened by loss of connectivity to their floodplains and hence reduced benefits from floodplain energy subsidies. Dryland rivers with ‘boom and bust’ ecological responses to flooding and extended dry periods may be particularly vulnerable. This paper describes variations in dietary composition of three fish species of contrasting trophic position in dryland floodplain lagoons with variable flood inundation and drying histories. The study species were Ambassis agassizii - a microphagic carnivore, Leiopotherapon unicolor - a carnivore/omnivore, and Nematalosa erebi - an algivore/detritivor. Despite the range of food items recorded in fish guts, each species fed mostly on relatively few food categories and few food items within each category. Most of the spatial (i.e. among lagoons) and temporal dietary variation was associated with different proportional contributions of these food items. Given the absence or low magnitude of flooding during the study period, temporal changes in diets of the three species are probably the result of successional changes in composition of invertebrate prey as the dry season progressed. The focus of each fish species on relatively few food categories and a few reliable food items within each category may be the most profitable foraging strategy when food resources are limiting in progressively drying floodplain lagoons.     

Hormonal correlates of being an innovative greylag goose, Anser anser

A number of studies have focused on the spread of foraging innovations within animal populations, but only rarely have individual dispositions of becoming innovative been considered. With two groups of individually marked, hand-reared greylag goslings we investigated hormonal and behavioural correlates related to the individual's ability to perform operant tasks. During individual tests 6 weeks after hatching, goslings were given small food containers covered by lids. In the following winter the sibling groups were tested in a social set-up at a food dispenser, which the geese could activate by pulling a flap. We analysed individual faecal samples collected at 2, 6 and 12 weeks of age, and also after the individual tests, for excreted corticosterone and testosterone metabolites by enzyme immunoassay. During the individual test, 18 of 23 individuals learned to remove the lids. These 18 birds excreted higher faecal corticosterone concentrations than their respective controls 2 weeks after hatching. At the food dispensers, only four males became food producers; all the others scrounged. These four were in the group of 18 that were successful in the individual test and again tended, although not significantly, to have higher faecal corticosterone 2 weeks after hatching than the scroungers. In one of the groups, excreted corticosterone increased and excreted testosterone decreased after the individual test. Goslings successfully removing lids at 6 weeks raised their faecal corticosterone to a significantly greater extent than the unsuccessful individuals. Our results suggest that becoming an innovator may be contingent upon individual coping styles. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Seasonality and life cycles of woody plant-feeding noctuid moths (Lepidoptera: Noctuidae) in Mediterranean habitats

Abstract.

• 1 The annual cycle of noctuid moths feeding as larvae on the foliage of eighteen woody plant species (belonging to ten different families) was studied at two southeastern Spanish Mediterranean forest habitats. Two questions were addressed in this study. (1) Does the rigorous (hot and dry) summer season characteristic of the Mediterranean-type climate impose a constraint on noctuid life histories? (2) Are there detectable differences in abundance or phenological patterns between the noctuid assemblages feeding on evergreen and winter-deciduous trees and shrubs?
• 2 Regardless of their leaf persistence habit, the majority of woody species studied had short shoot growth and leaf production periods in spring. Abundance of noctuid larvae peaked in May-June, shortly after host plants started to produce new leaves. Virtually no noctuid larvae were found on the foliage of the woody species studied at other times of year. Abundance and seasonal pattern of occurrence of larvae were similar on evergreen and deciduous food plants.
• 3 In contrast with the unimodal seasonal pattern exhibited by larvae, the abundance of adult moths (assessed by light trapping) showed two distinct peaks in early summer and early autumn, and a marked minimum in mid-summer.
• 4 Most woody plant-feeding noctuids recorded in this study (86% of species, about 95% of individuals) were univoltine. Univoltine species fell into one of two distinct life history categories, corresponding to pre- and post-summer flight periods. These two contrasting phenologies were associated with a bimodality in the duration of the pupal stage (‘short’ versus ‘long’), and were closely related to taxonomical affiliation at the subfamily level.
• 5 Within the ‘short’ pupal duration group, some species mate and oviposit shortly after emergence and pass the dry season in the egg stage, while others remain as potentially active, non-reproductive adults over most of the summer and mate by the end of that season. Species in the ‘long’ pupal duration group pass the summer in pupal or prepupal stage.
• 6 In the Mediterranean habitats studied, the adversity of the summer dry season seems to have led to a woody plant-feeding noctuid species assemblage almost entirely made up of univoltine species that concentrate their larval phases when suitable food (young leaves) is most abundant, and ‘avoid’ mid-summer as a flight time by emerging either shortly before or shortly after the adverse summer drought period. Year-round foliage availability afforded by dominant evergreen plants does not seem to have influenced the seasonal organization of noctuid cycles in any substantial way.