Hoverfly (Sirphidae) Wasp (Vespidae)

Tomasz W. Pyrcz

Zoological Museum

Jagiellonian University

www.mzuj.uj.edu.pl

Tropical ecology WBNZ800

Mimicry and other

related strategies

Mimicry was described based

on the example of tropical butterflies

Henry Bates (1862)Fritz Müller (1878)

A clearwing butterfly

of the subfamily Ithomiinae

Entries on „mimicry” on the Internet (Google)

In English – 42 000 000!

In Spanish – 978 000

In French – 611 000

In Polish – 46 700

MIMICRY

Mimicry is one of the fundamental issues of evolutionary biology

MIMICRY

Resemblance

Camouflage

Signalling

MIMICRY – a tripartite system

(model)

(mimic)

(operator)

Wickler, 1968

Vane-Wright, 1978

true

signal

false

signal

similar

appearance

Mimicry definitions

Mimicry (general definition) is the similarity of one species to another which

protects one or both.

Mimicry (Polish Wikipedia) – protective adaptations of animals (especially

insects) consisting in that harmless animals look like animals able to protect

themselves by taking their shapes or colours. They can also take shapes and

colous of the environment in order to be more difficult to detect.

Mimicry definitions

Mimicry (based on Wickler, 1968) is an evolutionary process in which an organism

improves its fitness by modifying its appearance towards another organism.

Mimicry (Pihneiro, 2004) involves an organism (the mimic) which simulates

signal properties of a second living organism (the model), which are received

as signals of interest by a third living organism (the operator), such that the mimic

gains in fitness as a result of the opertator identifying it as an example of the model

This definition does not say whether the fitness of model is affected!

CRYPSIS /MIMESIS

is not mimicry!

Differences between mimicry and crypsis:

Mimicry: 1. Mimic aims a response of the operator

2. Resemblance of the mimic modifies the fitness of the model

Crypsis: 1. Cryptical species are invisible to the operator

2. Resemblance has no effect on the fitness of the model

Ventral side of the wings closely resemble the pattern of lichens

Crypsis = camouflage

A butterfly of the subfamily Satyrinae

Ventral surface of the wings resembles dead leaves

Crypsis = camouflage

A butterfly of the subfamily Satyrinae

A locust of the subfamily Gomphocerinae

Camouflage – homomorphy i homochromy

A grasshopper of the family Tettigonidae

Camouflage – homomorphy and homochromy

Countershade – light ventral colours

and dark dorsal colours convert the

three dimesional the prey into an

illusion of a two dimensional object

Disruptive colours – colour

patterns interfers in the predator

perception of the real shape of the prey

Logitudinal dorsal line

of this toad is an additional

element of its disruptive

colours pattern

Crypsis – disruptive colours

When wings are wide open, the colour patterns of fore and hindwing alogns into a

pattern resembling wood corch, and at the same time disrupting the true body axis.

Crypsis – disruptive colours

A moth of the

genusThysania

Vane-Wright’s unified mimicry system

I Synergic warning Mullerian

II Synergic aggressive Angler fishes

III Synergic defensive Automimicry of Danaus

IV Synergic inviting Arithmetic

V Antergic inviting Maculinea myrmecophyly

VI Antergic defensive Batesian

VII Antergic aggressive Peckhammian, parasites

VIII Antergic warning obnoxious Reduviids predators

THE OPERATOR

The identification of the operator is crucial. Without identifying the operator

we cannot dissuss mimicry.

MODEL PROTECTION

Unpalatability as the protective measure is the backbone of the mimicry theory.

Key issues related with mimicry

COEXISTENCE IN TIME AND SPACE

Microsympatry is the first precondition of turning up of mimicry.

Most authors agree that mimics and models have to coexist in time and space

so that the signal can be functional

RELATIVE FREQUENCY

All kinds of mimicry are frequency dependent. The theory of Batesian

mimicry infers that the model has to be abundant in the environment so that

the system can be operational, and most authors agree that it has to occur at

higher frequency than the mimic.

Key issues related with mimicry

MIMICRYin other words:

DECEPTION

Mating moths of the family Syntomiidae, excellent mimics of wasps

VI - Batesian mimicry

VI - Batesian mimicry

Day active moths of the family

Tortricidae have a similar colour

pattern and beahviour as toxic bugs

VI - Batesian mimicry

Day active moths of the family

Sesiidae have a similar colour

patterns as wasps and bees

VII - Myrmecomorphy –

mimicry of ants by other organisms

Salticidae spiders copy the shape and behaviour

of Oecophylla ants in order to prey on them

Mimicry can be aggresive or defensive

V - Myrmecophily

butterfly larvae and ants

Myrmecophily are different associations of ants with other organisms, butterflies,

bugs, aphids, grasshoppers etc. Larvae of Lycaenidae produce sweet secretions

which attract the ants, that take it to the nest, where they are given shelter from

predators and parasitoids. Some caterpillars, such as M. arion feed on ants larvae.

False eyes:

„Owl eyes” of a Caligo

butterfly (Brassolinae)

VI - Auto-mimicry?

Defensive mimicry

II – Auto-mimicry / Luring to baits

Deep sea angler fishes emit bioluminiscent light

from the illicium - a fleshy head grow, a modified spine

VI - Defensive mimicry

Egg dummies

Pasion fruit, Passiflora, host plant of Heliconius butterflies

produces galls resembling by the their shape and colours butterfly eggs

V. Inviting mimicry

Bee-like orchids

www.conservationreport.files.wordpress.com

The petals of thic orchid look like a female bee in order to

attract male bees which take part in the pollinization of this flower.

We have to be able to identify the operator.

Otherwise, we can’t talk about mimicry.

MODEL

MIMIC

OPERATOR?

Proteles

Striped hyena

Females of an Asian swallowtail Papilio polytes are polymorphic and mimic

unpalatable Pachliopta species. Males are monomorphic and non-mimetic.

Sex limited mimicry

Kunte, 2009

Sex limited mimicry

Mimicry used in phylogenetical studies

Some females of African swallowtail Papilio dardanus mimic not the

obnoxious model Amauris but instead the male of its own species.

Danaus sp.

Amauris sp.

Amauris sp.

male

Papilio dardanus

andromorphic female

Papilio dardanus

females

Papilio

dardanus

Auto mimicry: when mimic and

model belong to the same species

„MULLERIAN MIMICRY” IS NOT MIMICRY!

Repeating the same aposematic colour pattern by protected species

enhances the warning signal adressed to potential predators

Enhancing the aposematic signal

Batesian mimicry: model’s fitness decreases

Müllerian mimicry: model’s fitness increases

ACCIDENTAL resemblances between insects are to be expected.

The immense number of species and the necessary limitation in the

variety of colours and patterns must lead to coincidences.

The coincidences would be relatively more numerous when

the patterns are simple. Poulton, 1903

Non-venenous snake (Lampropeltis sp.) – on the right

Venomous coral snake (Micrurus sp.) – on the left

VI. Emsleyan/Mertensian mimicry

Predators either prefer or reject ringed preys

Pfennig et al., 2004

VI. Batesian mimicry: evidence from the field

Heliconius (Nymphalidae) and jacamars (Galbulidae)

VI. Batesian mimicry: experimental evidence

Photo: Brandao (Flickriver)

Wild rufous-tailed jacamars (Calbula rujcaudu) prey frequently upon butterflies

in Costa Rica.

Individually caged birds were tested with over 1000 butterflies of 14 morphs.

Both wild jacamars and the two captive individuals were able to capture and

handle local butterflies.

Butterflies were recognized by the jacamars as prey through their movement.

Captive birds discriminated between an unacceptable group of butterflies, which

generally fly slowly or regularly, are warningly coloured and mimetic, with

transparent, or white, red, black coloration, and an acceptable group that generally

fly fast or erratically, or are cryptic.

Chai, 1986

VI. Batesian mimicry: experimental evidence

Morphological and behavioural characteristics of butterflies help the jacamars to

assess their palatability. Individuals of unacceptable butterflies were sight-rejected.

In cases when the above butterflies were attacked, they were quickly released and

usually unharmed.

In contrast, palatable butterflies were usually quickly attacked and consumed.

Captive jacamars were able to discriminate between the very similar colour

patterns of some Batesian mimics and their models, and could memorize the

palatability of a large variety of butterflies.

Chai, 1986

VI. Batesian mimicry: experimental evidence

Captive female bird, after long periods without food, consumed many pierid and

heliconiine butterflies that were consistently rejected by the male for their

distasteful and dangerous qualities.

Chai, 1986

VI. Batesian mimicry: experimental evidence

Locomotor mimicry

Locomotor and escape mimicry concepts

(Srygley, 1999).

Motion of the prey increases selection

against odd individuals.

Locomotor mimicry may occur between

palatable species that are alike as a

result of the so-called „unprofitable prey

factor”.

By frustration learning, the predator

associates the colour of the prey

with unprofitability.

IV. Arithmertic mimicry

A particular case of the synergic inviting mimicry (Vane-Wright, 1976),

the "safety in numbers" and "lost in a crowd" effect

Adelpha in Venezuela have six local subspecies all characterised by HWD

bands suffused along their distal edge with orange.

Arithmetic mimicry is a system acting through co-convergence of the

participants signal,w hich increases its effectiveness, as in Müllerian mimicry,.

Butterflies of the genus Actinote

have the ability of syntesising

strong cyagenic toxins

for example linamarins

IV. Arithmertic mimicry

Limacodidae moth caterpillar

Warning – colours and shapes

Parasitoid egg

dummies

First to fourth instar lavae of Paplio butterflies look like bird dropping

Last instar changes into snake-like

Mimicry strategies can shift within individual’s life span

Dual signals

camouflage and warning

North American moth of the Saturniidae family

Signal interpretation problems: Aposematic?

The effect of warning colours

of this beattle is reinforced by the

protrusions on the antennae

Thorough protection

Setae and scoli

reducing the possibility

of parasitoid

flies and wasps

Lighter band

mimics a culm

Green colour of the

body perfectly matches

the shade of green of

the host plant leaf

Caterpillars of the Saturniidae family

Mimicy is functional only when the model and the mimic

coexist in time and space!

-Overlapping altitudinal ranges

-Overlapping geographic ranges

-Different

altitudinal

ranges

-Overlapping

geographic

ranges

Different

altitudinal

ranges

-Different

geographic

ranges

When is mimicry ESS?

The evolutionary rationale of (Batesian) mimicry: predator avoidance

Signal’s function is different: directed to the mate – infraspecific communication

When predator’s pressure on survival is above a threshold limit

But if predators’s pressure is not a limiting factor

…is aposematic and addressed to the predator

Signal (for example): bright colours..

?

??

?THE PITFALLS OF

INTERPRETATION

Are insectivorous birds

an important limiting

factor controlling

the populations of butterflies?

Unprofitable prey factor

Predators learn that some preys are too diffucult to catch, thus consider them as

„unprofitable” and do not prey upon them, except for opportunistic events.

?

Too small!

Too fast!

Too difficult

to detect!

Wings big

Body too small!

Does gain compensate the energy spent on its acquirementt ?

Mimicry case study: Lymanopoda and Cheimas butterflies

Sympatric species with similar colour patterns occur in the same areas

Mimicry case study: Lymanopoda and Cheimas butterflies

Sympatric species with similar colour patterns occur in the same areas

Mimicry case study: Lymanopoda and Cheimas butterflies

Sympatric species with similar colour patterns occur within same elevational bands

Brown butterflies mimicry: no protection involved!

Colour pattern resemblance are common among sympatric species of the tribe Pronophilini

Mimicry case study: Lymanopoda and Cheimas butterflies

ANTI-APOSTATIC SELECTION

Anti-apostatic selection is the selection against the odd individuals.

It arises when preys are at high frequency and predators feed

disproportionately on rare prey.

This process leads to a decrease in variation within prey populations.

Most evidence comes from experiments using artificial prey.

There are proofs that predators can be selective on prey frequency

and target the individuals whose pattern is at low abundance.

Mimicry case study: Lymanopoda and Cheimas butterflies

ANTI-APOSTATIC SELECTION

Anti-apostatic selection favours gregarious behaviour.

Anti-apostatic selection is theoretically unlikely to evolve when

predators specialize on a given prey. If so, predation on rare

phenotypes would be unprofitable energetically.

However, in a situation when preys are at high frequency and

predation is random and/or opportunistic, the evolution of anti-

apostatic selection is plausible.

Moth biomass exeeds

the biomass of butterflies

by several magnitudes!

Resting moths: easy prey

-ESS strategy: crypsis

- No aposematic colours

Recommended literature in Polish:

1. H. Krzanowska et al., 2002. Zarys mechanizmów ewolucji

2. J. Koszteyn, 2005. Zjawisko mimikry a problem orientacji i decepcji

in English:

3. Ruxton, Sherratt & Speed, 2005. Avoiding attack

Spider looking like a bird dropping

What kind of mimicry would that be?

Some ants resemble spiders

What kind of mimicry would that be?