The extent to which a species can adapt to an anthropogenically influenced environment is dependent on the evolutionary history of the species, the antipredatory adaptations of the population under study, the individual experiences, tolerances and learning capacities of animals, and their sensory limitations.

1. BEHAVIOR IN CHANGING
ENVIRONMENT
AKANSHA GANGULY
MB0415
DEPARTMENT OF BIOTECHNOLOGY
OCTOBER 2016

2. I. MECHANISMS OF BEHAVIOUR

3. INTRODUCTION
• Both genes and the environment have crucial importance in shaping animal behaviour
• Learning : change of behaviour induced by experience, which provides animals with an
opportunity to adapt their behaviour to suit contemporary environments. It is the primary
mechanisms animals use to cope with shifting environmental variables. Changes in behaviour
as a result of experience can also be induced through mechanisms other than learning, for
example by physiological shifts, but here we are primarily concerned with cognitive changes
induced by neural plasticity
• Anthropogenic influence on behaviour change:
Human affected landscapes are characterized by large-scale land clearance for farming or
industry, and by urbanization as human populations increasingly consolidate in cities.

4. INNATE AND LEARNED RESPONSE: EFFECT ON
NEURAL MATTER
• Innate mechanisms often act as filters to focus the attention of the animal on environmental cues that are likely to be
biologically meaningful.
• Learning then enables the animal to make associations between cues or outcomes through classical or operant
conditioning.
• Rats Rattus norvegicus are more likely to associate gastric illness with olfactory cues rather than mechanical ones
(e.g. electric shock or flashing lights).
• Fish have a strong preference for red coloured objects because red is associated with high quality foods. Guppies can
be taught to find a food reward hidden behind a red partition far more quickly than if the partition is any other
colour.
• Salmon Salmo salar par reared in enriched environments, are better able to generalize between food types and thus
learn to forage on novel prey items more quickly than those reared in impoverished conditions.
• Butterflies that have a high capacity to learn the location of host plants have larger mushroom bodies in their brains.
• Male meadow vole Microtus pennsylvanicus brain size increases during the breading season in line with the
increasing size of his territory.
• Black-capped chickadees Poecile atricapillus increase their brain size during autumn when they are busy caching food
items for the coming winter.

5. DEVELOPMENT OF ANIMAL BEHAVIOUR
• Controlled by two underlying mechanisms:
a. An automated response to specific stimuli within the environment that is entirely predetermined by
specific genes (innate).
b. modification of behaviour through experience and interaction with stimuli in the environment during
an individual’s lifetime.
• The combination of innate and learned behaviour that best tracks environmental change will result in
the optimal behavioural phenotype. This will depend on the degree to which the environment is stable
and, hence, predictable through space and time.

6. SPATIAL HOMOGENEITY
1. Individual level: the appropriate spatial scale is that of the home range. That is the environment in which the
individual operates and where the fitness benefits associated with performing certain behaviours are
relevant.
2. Population level: potential for immigration and emigration from local microenvironments, where individuals
may experience a range of alternative environmental variables.
3. Species level: most appropriate spatial scale. Environment is less likely to be homogeneous and behaviour
will need to be increasingly plastic to cope with this variability.
Thus, learning plays a larger role in shaping the behaviour of species that occupy large geographical areas that
encompass a variety of environmental conditions

7. TEMPORAL HOMOGENEITY
• Conditions for learning in temporal stability:
a. Firstly, the degree to which the environment is temporally stable during the lifetime of an individual. If the
environment is highly stable there will be little need for the individual to display behavioural plasticity and
innate behaviours should dominate. At intermediate levels of temporal heterogeneity, learning should
prevail since innate responses will not be sufficient to track environmental variability.
b. Secondly, the intergenerational scale concerns the degree to which the environment is stable from one
generation to the next. In circumstances where the environment is temporally stable over many
generations, behavioural traits can become genetically fixed in the population. But, if there is temporal
environmental variance between generations then plasticity will be favoured.
Because environments are variable in space and time, no given phenotype will ever be consistently optimal and
some degree of phenotypic plasticity is required.

8. ENDOCRINE HOMEOSTASIS IN CHANGING
ENVIRONMENT
• The endocrine system regulates adaptive physiological changes, such as the onset and maintenance of a
reproductive state, aggression, fat stores, metabolic turnover, and secondary sexual traits amongst
other factors

9. PHOTOPERIODISM AND CLIMATE CHANGE
• The advent of elevated temperatures and changes to rainfall patterns associated with global climate change
may have important implications for the timing of life history stages of animals, resulting in alterations of the
onset, duration, or termination of events, such as reproductive periods or migration.
• Photoperiodism is crucial for initiating physiological and developmental processes across a range of taxa,
including molluscs, arthropods, fish, frogs, birds, and mammals.
• Supplementary cues such as food supply, temperature, weather conditions, and behavioural stimuli can
modify the effects of photoperiod to advance or delay the timing of reproduction.
• Under controlled photoperiod, female white-crowned sparrows Zonotrichia leucophrys show greater follicular
development at higher temperatures.
Source: Google Images

10. • Female great tits Parus major lay eggs earlier in elevated temperatures with a much smaller temperature
difference between groups.
• In mammals, photoperiod cues are essential for synchronizing seasonal changes in physiology and behaviour.
• Large bodied, longer-lived mammals tend to show a higher degree of photoperiodic cueing of reproduction,
whilst smaller bodied mammals respond more to environmental cues, such as temperature or rainfall.
Where there is a mismatch between seasonal environmental cues and photoperiodic cues, as is predicted under
climate change forecasts, it may be these longer-lived mammalian species which are more affected.
Source: Google Images

11. THE EFFECTS OF URBANIZATION
• The urban environment as a new type of ecosystem significantly differs from nearby non-urban ‘natural’
habitats in a variety of abiotic and biotic factors; may suffer less from climatic stress especially during the
winter months, due to the warmer microclimate (‘heat island effect’) or from lower predations risk.
• Many novel and potentially stressful conditions rarely experienced in their original, ‘natural’
environments:
a. Unfamiliar food sources
b. Elevated anthropogenic disturbance
c. Permanent presence and high density of humans, dogs, and cats
d. Increased levels of artificial lighting and noise.

12. • Reduced acute corticosterone stress response in urban European blackbirds Turdus merula compared to
rural blackbirds has been interpreted as a result of local adaptation to the urban-specific environmental
condition.
• Altered light irradiance in urban areas has been suggested to influence daily and seasonal organization,
such as foraging behaviour, reproduction, migration, and communication.
• A possible candidate which triggers these behavioural responses is the hormone melatonin (part of
central pacemaking system of the body).

13. II. RESPONSE TO CHANGE IN ENVIRONMENT

14. DISPERSAL
• The decision to disperse is fundamentally a behavioural process that allows individuals to move from one
environment to another in order to find the best possible environmental conditions for reproduction.
• Dispersal—usually movement by juveniles and, less frequently, by adults—leads to shifts in population sizes in
habitat patches and the transfer of genes among patches, thereby altering the genetic make-up of populations
across the landscape. Dispersal behaviour is often highly plastic and condition dependent.
• Dispersal can be viewed as a process carried out during three connected phases which are independently
affected by changing environments:
a. Departure
b. Movement
c. Colonization

15. • Wolf spiders Pardosa purbeckensis alter their decision to disperse via passive aerial transport depending
on the strength of the winds, which determine their ability to find suitable habitats.
• Highly dispersive genotypes of Tetrahymena ciliates become more streamlined and grow a flagellum
for more efficient travel and also have a much higher reproductive rate which increases their
colonization success.

16. • Anthropogenic disturbances interact with dispersal, including
(1) Changed patch quality,
(2) Habitat fragmentation,
(3) Species invasion,
(4) Ecological traps.
• Evidence from genetic analysis shows that the fragmentation of habitats by roads in north-eastern
America has reduced the movement of timber rattlesnakes Crotalus horridus and led to full separation
of their winter dens.
• Indigo buntings Passerina cyanea prefer to nest in natural edge habitats, as these provide excellent
nesting and foraging opportunities. Yet, their nesting success in anthropogenically created edge habitat
is low because these habitats contain more nest predators.

17. MIGRATION
• Depending on a species’ life history, migration can involve multiple, repeated journeys (e.g. wildebeest)
or a terminal, once-in-a-lifetime event (e.g. salmon). All these examples are commonly referred to as
migration.
• Environmental change can affect migration by
a. altering conditions along the migration route or at the breeding and non-breeding areas, and
b. by influencing the cues that are used in the timing of migration.
• Building of dams and weirs impede the migration of chinook salmon Oncorhynchus tshawytscha.
• Even birds that are potentially capable of flying over destroyed or altered habitats can be affected by
habitat modification since very few species migrate in one single trip but must, instead, rest and feed
along the way. This is especially important for ‘capital breeders’, which mainly rely on body resources for
egg production (that are built up in the wintering areas or staging sites along the migration route).
• Drastic habitat changes, such as large scale clear-cut logging, can undermine the efficacy of
topographical ’cues’ that are often used by migratory birds.

18. • Environmental conditions change during the season and consequently there will be an optimal ‘time
window’ for life cycle events such as migration or breeding. For example, individuals that arrive too
early at the breeding area could be confronted with harsh environmental conditions and, as a result,
may not survive. However, if they arrive too late, they may miss out on gaining access to the best
breeding sites and/or mates, or the optimal time window for breeding may close (i.e. environmental
conditions deteriorate too soon for breeding to be successful).
• Sockeye salmon Oncorhynchus nerka migrate earlier under warmer river temperatures; the time when
migrating song thrushes Turdus philomelos pass the Rybachy ringing station in the southeast Baltic
depends on both the frequency and strength of tail winds over Europe.
• Warming climate has advanced the phenology of many traits,
including migration time. Migration time of birds and salmon is better studied
than in many other species, but our knowledge is far from complete.

19. FORAGING
• Classical foraging theory considers behavioural modifications in response to changes in the type and
array of food available and has, in recent years, also considered how foraging behaviour should adjust to
predation danger.
• Two major influences are recognized as crucial with regard to individual foraging decisions.
(1) ‘economics’ (handling time, encounter rate etc.; the stuff of classic ‘optimal foraging theory’), and
(2) the ‘risk of predation’.
• Animals are very flexible foragers, and able to adjust their foraging behaviour as circumstances change.
Changes considered in most of these studies are generally encountered naturally (e.g. weather, vole
cycles). Rapid anthropogenic changes to the environment may bring foraging situations that have not
been encountered in a species’ evolutionary history,

20. • The best-known examples are the sudden appearance in the environment of novel chemicals, such as
DDT, bioaccumulations of which were very injurious to top predators. There are natural analogues also.
• The invasion of the toxic cane toad Rhinella marina in Australia has been lethal for the populations of
toad-eating snakes along the invasion front.
• Demonstrating behavioural ‘flexibility’ with respect to foraging would require:
(1) identifying the various states of the environment (e.g. good vs. poor weather; high vs. low years, etc.)
(2) the behavioural tactics available to the forager (e.g. diet choice)
(3) the performance in each environment of the forager using these behavioural tactics.
• There are a very large number of ways that animals could alter foraging behaviour to increase safety,
by adjusting the selection of places, times, techniques, or diet.
• Many aquatic creatures undergo ‘vertical migration’, travelling to the surface at night (or at dawn and
dusk) to feed in relative safety.

21. • CASE STUDY- reintroduction of wolves Canis lupus to Yellowstone National Park
1. The threat posed by wolves forced their main prey species, elk Cervus elephus , to become much more
cautious while foraging, restricting their grazing and browsing to the safest places.
2. The attendant release from herbivory allowed thickets to regenerate, which enabled the return of
beavers Castor canadensis to the park.
3. The ‘ecosystem engineering’ effects of beavers in turn affected the park’s hydrology. Effects on insect
biodiversity and avian breeding success could also be traced to the antipredator behaviour of the elk.

22. CONCLUSION
• Behavioural traits related to consumption and nutrient cycling, in particular, can cause widespread effects
on ecosystems. Therefore, rapid changes to these traits due to phenotypic plasticity and contemporary
evolution may cause important changes to ecosystems.
• If populations are adversely affected by such changes, they need to reduce the mismatch through
immediate behavioural responses, phenotypic (developmental) plasticity, or evolution.
• The extent to which a species can adapt to an anthropogenically influenced environment is dependent on
the evolutionary history of the species, the antipredatory adaptations of the population under study, the
individual experiences, tolerances and learning capacities of animals, and their sensory limitations.

23. REFERENCES
• Candolin, Ulrika, and Bob BM Wong, eds. Behavioural responses to a changing world:
mechanisms and consequences. OUP Oxford, 2012.
• Wong, Bob BM, and Ulrika Candolin. "Behavioral responses to changing
environments." Behavioral Ecology 26, no. 3 (2015): 665-673.
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