Интересный сборник по эволюции социального поведения.
The Ecology of Altruism in a Clonal Insect. Nathan Pike and William A. Foster - идеальный модельный объект - тли. У них чередуются бесполые поколения и половые, так что можно изучать изолированно на одном объекте влияние генетических и экологических факторов. Тем более что есть социальные тли. около 60 видов формируют галлы, в которых живут колониями, у них выделются морфы солдат, защищающие колонию... То есть жертвующие собой. Авторы со всех сторон смотрят на этих колониальных тлей и вроде бы у них получается, что внегенетические (экологические) факторы очень существенны для социальной жизни.
Тли реагируют на хищников и своей численностью, и расположением колоний, и долей солдат. Интересно, что если искусственно снизить число муравьев, связанных с данной колонией тлей, то у тлей вырастает число солдат. То есть колония тлей в самом деле делегирует функцию защиты муравьям, а коли тех нету - растит своих солдат.
It is clear that the importance of relatedness has been overemphasized in many studies of social evolution – especially in the social insects. This is partly because relatedness is relatively easy both to define and to measure but also because of the seductive complexity inherent in the reproductive asymmetries of the social Hymenoptera. However, although relatedness is clearly an essential component of any kin-selected explanation of sociality, it would be foolish to suggest, as some have done, that there should be any simple relationship between levels of relatedness and eusociality. In essence, relatedness merely sets the threshold that must be overcome by the ecological determinants of the costs and benefits of helping. In probably all social animals, it is the ecological context that drives the evolution of altruism. The social aphids make this point rather clearly. All aphids have what seems like a strong genetic predisposition to help, since they are potentially interacting within a single clone, but yet social aphids are rare. The critical factors that determine whether sociality evolves are to do with the ecological context that affects both the level of clonal purity and the costs and benefits of helping.
The Evolutionary Ecology of Eusociality in Australian Gall Thrips: a ‘Model Clades’ Approach
Thomas W. Chapman, Bernard J. Crespi, and Scott P. Perry
Это о колониях трипсов, у которых тоже есть солдаты и тоже можно приуинуть, что там с эволюцией эусоциальности у трипсов
Солдат у трипсов открыли в 90х годах. Эта каста возникает незаивсимо в разных эволюционных линиях, видимо в связи с переходом на акацию. Видимо, влияют нападения клептопаразитов - если их становится много, солдаты у трипсов появляются чаще.
Our studies have several broad implications for the study of animal social evolution.
First, gall-inducing thrips support the ‘factory-fortress’ model for the evolution of
eusociality (Alexander et al. 1991; Crespi 1994; Queller and Strassmann 1998).
Thus, they exhibit high relatedness due in part to their claustral habitat, strong pres-
sure from natural enemies due to the extremely high value of their nest resource,
and the ability to defend against these enemies, using weaponry that originated in
a different selective context. These findings support the hypothesis that there are
two more or less discrete ‘modes’ of eusociality: ‘factory fortress’ species that
include gall thrips, gall aphids, some termites, snapping shrimp, some mole rats,
and a species of ambrosia beetle; by contrast, ‘life-insurers’ or ‘forager-defenders’,
include most eusocial Hymenoptera and some social birds and mammals (Choe and
Alloparental care and eusociality have apparently been favored by
considerably different selective pressures across these two modes of sociality, and
broad-scale comparative studies on the causes of social evolution should consider
them separately. Indeed, our findings suggest that the three main components of
eusociality, behavioral, reproductive, and morphological divergence between more-
reproductive and more-helpful individuals, evolve in a different sequence for fac-
tory-fortress social forms than for eusocial taxa with foraging workers (Chapman
et al. 2002; Thorne et al. 2003). Thus, in gall-inducing Acacia thrips, morphologi-
cal and behavioral differences between soldiers and dispersers apparently evolved
before strong reproductive skew; by contrast, the usual scenario for Hymenoptera
is that behavioral divergence evolves in conjunction with high skew, and that mor-
phological divergence can evolve only after these two conditions have been met
(Wilson 1971; Bourke and Franks 1995). We have hypothesized that the factory-
fortress route to sociality differs because defense trades off less strongly with
reproduction than does energetically demanding foraging, and because defensive
morphology makes reproductive domination by foundresses less likely (Chapman
et al. 2002).
The Ecology and Evolution of Helping in Hover Wasps (Hymenoptera: Stenogastrinae )
статья по осам-стеногастринам (вроде банально - там самке помогают другие самки, обсуждается, с чего бы им помогать). Гнездо с нуля поднять - дорого и рискованно, потому есть стратегия хоть помочь родственнице - у которой уже есть гнездо. Индивидуальные вариации помогающего поведения.
One similarity between cooperatively breeding vertebrates and stenogastrines in
particular among wasps may be that resource inheritance is a significant benefit of
remaining on the natal nest (as also in termites: Korb, this volume). Two features
of stenogastrines underlie this. First, stenogastrine groups are always small, so that
helpers may always have a reasonable chance of outliving individuals ahead of
them in the queue to inherit (Field et al. 1999; Shreeves and Field 2002). Second,
stenogastrine helpers can potentially wait indefinitely for their chance to inherit.
This is a consequence of their relatively aseasonal tropical environment, in which
there is no absolute winter to truncate the lives of individuals waiting in the queue.
Whether the chance of inheritance in stenogastrines is quantitatively similar to that
in vertebrates remains to be seen, however, particularly given the significantly higher
survivorship of the dominant egg-layer compared to her helpers in L. flavolineata
(Field et al. 1999; Shreeves and Field 2002)
Why are so Many Bees but so Few Digger Wasps Social? The Effect of Provisioning Mode and Helper Efficiency on the Distribution of Sociality Among the Apoidea
Erhard Strohm and Jurgen Liebig
Сравнение пчел и ос-сфецид - отчего в какой группе чаще социальность.
Furthermore, the evolution of sociality might be
facilitated if foundresses can save investment by providing sexuals and helpers only
with the resources that are necessary for their respective task. Such a task-related
investment for progeny might be much easier in bees than in sphecids, since the
former can provide pollen of different plant species and different proportions of
nectar whereas the latter cannot control the quality of the larval food to such an
extent. The large size of the prey of sphecids has also enabled a unique strategy
of oviposition for larval parasites. Flies and cuckoo wasps might oviposit on the
prey while it is carried to the nest by a sphecid female. This “out-of-nest” parasit-
ism cannot be countered by communal nesting, for example, making early steps of
sociality less beneficial than in bees where this type of parasitism does not occur.
We conclude that one of the most basic ecological features, the type of resource
used for provisioning , might have far-reaching consequences for the evolution of
sociality in the Hymenoptera
We hypothesized that the basic difference between bees and sphecid
wasps, the type of larval provisions, might have had crucial consequences for the
evolution of sociality.
The large prey of sphecids results in a close relationship between body size and
reproductive success . Therefore, small workers would be of no particular help. This
is different in bees. Pollen allows being collected in small packages adjusted to the
body size of the foraging individual. Thus, a reduced body size does not necessarily
change the efficiency of a bee. Assuming that the resources for reproduction are
limited, a mother might spare investment by producing helpers that lack the ability
to found a nest on their own. This would require that the founding and provisioning
abilities can be separated. Such a possibility is less likely in sphecids, because the
large prey does not allow mother sphecids to finely adjust the quantity and quality
of provisions with regard to the prospective reproductive potential of their progeny.
Bees, by contrast, have much more opportunity to provide their progeny with a
specific diet that might predispose their progeny to become helpers. The type of
provision can thus influence whether cheap helpers are efficient in provisioning that
allows them to gain indirect fitness benefits.
Social Plasticity: Ecology, Genetics, and the Structure of Ant Societies
Instead, major features of the colony phenotype, such as worker number, queen number , reproductive skew , worker policing , and the pattern of allocation of resources towards colony growth or reproduction are more strongly affected by variation in ecological parameters, such as the availability of suitable nest sites for colony founding, resource abundance and the occurrence of social parasites
У пчел в улье некоторые генетические линии специализированы для понимания танца, принесения воды или защиты гнезда Robinson and Page 1988, 1989; Page and Robinson 1990. Есть данные, что полиморфизм рабочих Camponotus and Acromyrmex тоже генетически детерминирован Fraser et al. 2000; Hughes et al. 2003; Julian and Fewell 2004
The Ecology of Social Evolution in Termites
Обзор с рассмотрением систематики термитов, общих черт экологии и пр.
Kin-Recognition Mechanisms in Cooperative Breeding Systems: Ecological Causes and Behavioral Consequences of Variation
Jan Komdeur, David S. Richardson, and Ben Hatchwell
Обзор теории отбора родственников. Способы распознавания родственников.
Social Ecology of Horses
Horses obviously realize the social composition
of their group and are even able to determine their own position in it. The horses’
exceedingly flexible social behavior eagerly demands for explanations about the
cognitive mechanisms, which allow horses to determine their individual decisions.
As Nicol (2002) already claimed, there is an urgent need for specific research on
horses’ cognitive abilities. Aside from basic cognitive research, especially, the
assumption for the existence of alliances in horses (Feh 1999) needs to be evaluated
African Mole-Rats: Eusociality, Relatedness and Ecological Constraints
M. Justin O’Riain and Chris G. Faulkes
Социальная экология эусоциальных млекопитающих. Обзор систематики и экологии близких родов. Социальность в филогенетической линии возникала минимум дважды. Cryptomys, Heterocephalus
Eusociality is a special form of sociality that has interested biologists since
Darwin first considered the existence of sterile castes as a special difficulty for
the theory of natural selection. The term ‘eusocial’ was originally used to describe
groups of insects living in close-knit communities but where there is a reproduc-
tive division of labor.
Thus the evolutionary inception of
sociality is argued to be parental retention of offspring in the natal territory and the
question thus becomes: what factors promote sociality as a successful lifestyle,
given the obvious direct fitness benefits? Burda et al. (2000) state, that the AFDH
may provide an explanation for why cooperative foraging is necessary for survival
in an arid habitat. Following on directly from this we suggest that deriving the cri-
teria of eusociality thereafter is relatively simple: (1) parents maintain a monopoly
on reproduction because of incest avoidance (2) there is an overlap of generations
because of the high costs and risks associated with offspring dispersal and inde-
pendent foraging and (3) cooperative care of the young born to the colony is
expected because helping to raise related young is the best way for offspring, that
cannot breed independently, to increase their inclusive fitness (Hamilton 1964).
Самки, по неопубликованным данным, могут жить 27 лет, очень много для мелких млекопитающих.
Ultimate evolutionary factors that have been recognized as important to the evolu-
tion of sociality in mammals are (1) predator vigilance and protection, e.g., meerkats
(Clutton-Brock et al. 1998), dwarf mongoose (Rasa 1977), naked mole-rats
(Alexander et al. 1991); and (2) increased efficiency in procuring food, e.g., naked
mole-rats (Jarvis 1985), Damaraland mole-rats (Jarvis and Bennett 1993), wild dog
(Frame et al. 1979) and wolves (Zimen 1975). Burda et al. (2000) suggest that the
ultimate evolutionary reason for eusociality in mole-rats is that it is a phylogeneti-
cally constrained phenomenon resulting from a social common ancestor of the
We conclude that it is not possible to rule out the
influence of kin-selection because all vertebrate social groups are formed through
natal philopatry (i.e., the subsocial evolutionary route). However, relatedness alone
is inadequate to explain the variation in sociality evident both within the family and
within species. Ecological constraints emerge as the most significant selective
factor for group formation and ultimately, the evolution of castes in the most social
of all mammals—the naked mole-rat.