PARENTAL CARE IN INSECTs

Archana Anokhe
Roll. No - 20416

 INTRODUCTION
THE EVOLUTION OF PARENTAL CARE IN INSECTS
FORMS OF PARENTAL CARE
MALE VERSES FEMALE CARE
HORMONAL REGULATION & CHEMICAL SIGNALING IN PARENTAL CARE

COST& BENEFITS OF PARENTAL CARE

CASE STUDY

INTRODUCTION
Parental care - any post-ovipositional behaviour that promotes survival, growth, &
development of offspring

(Tallamy et al.,1984)

A prime example - altruistic trait evolved to enhance the fitness of the recipients
(offspring) at the expense to the donor (parents)

(Royle et al., 2012)

Classified into 3 groups:

Protect offspring

Protect resources needed by the offspring

Improve resources

(Wood et al.,1991)

THE EVOLUTION OF PARENTAL CARE (PC) IN

INSECTS

Ecological factors - harsh environments, ephemeral food sources or predation

pressure

Harsh
environment

Ephemeral
food

Predation
pressure

Contd..

Harsh environmental conditions

Egg attendance provides an alternative route to resist harsh environment

For e.g.- staphylinid beetle, Bledius spectabilis live in intertidal saltmarsh, to prevent
flooding of their nest and anoxia of their eggs, females provide care in the form of closing &

reopening of the burrow

Ephemeral or distant food sources and specialized foraging

Burrower bug, Sehirus cinctus nymphs only eat seeds of Prunella spp. & are available for a

few weeks of spring, so mothers has to compete for this resource with in a short time span
Specialized food of Cryptocercus spp. underlies the evolution of PC

(Tallamy et al., 2007)

Contd..

Cont..

Do natural enemies drive the evolution of PC ?

Predation play an important role in the evolution of parental care
In the shield bug, Elasmucha spp. females shelter the eggs and nymphs by covering
them with their body and fanning their wings when attacked
European beewolf (Philanthus triangulum), females provision brood cells with
paralysed honeybee

(Tallamy et al., 2007)

FORMS OF PARENTAL CARE

Diversity of social behaviour among the invertebrates - asset and

challenge
Richness present in both number & forms of care provided by
parents
50 families of arthropod have evolved parental care
(Costa et al.,2006)

Cont..
Types

1. Trophic egg productions

2. Attending eggs and offspring

Example
Plassid beetle Cylindrocaulus patalis
Treehopper Umbonia crassicornus

3. Protection and facilitating feeding of

mobile young
a.
b.
c.
d.
e.

Guarding young
Poised to defend
Egg dumping or brood mixing
Formidable mother
Blocking entry

a.
b.
c.
d.
e.

Fungus feeding beetles Pselaphacus sps

Assassin bug & Shield bugs
European Earwig Forficula auricularia
Praying mantis Oxyophthalmellus somalicus
Myrmecine and Zacryptocerus varians

5. Nest building and burrowing

a.
Hiding evidence
b.
Deceiving enemies

a. Solitary wasp
b. Bembix sand wasps

6. Brooding behavior & viviparity

Webspinner (Partenembia reclusa)

Contd..
1. Trophic egg productions

To making the correct choice of which eggs to consume, chemical cues is incorporated into the
trophic egg
Passalid beetle ,if 3rd instar larvae stridulate, they are fed by trophic egg
(Philipi et al., 2008)

Burrower bug , Sehirus cinctus produce some trophic eggs at the time when they produce viable
eggs as well as after the nymphs hatch. It provide food , when mother go for foraging
(Hironaka et al., 2005)

Contd..
2. Attending eggs and offspring

Treehopper Umbonia crassicornus, mothers tilt their elongated pronotum and fan the potential threats,
protecting their young until adulthood

Offspring produce synchronous vibrations that inform the mother on which side threat is more
prominent

(Ramaswamy et al., 2009)

3. Protection of mobile young

Mobile young feeding in open area vulnerable to predators & parasitoids

Females standing nearby, not only threatening potential predators, but also stroking wandering
nymphs (Lace bug)
(Windsor et al., 1994)

Contd..
a.

Guarding young:- Brazilian sawfly, Themos olfersii, continues guarding their larvae even when they
fully sclerotized & starts feeding

b.

Blocking entry:- In myrmecine colony major worker blocks entrance with its saucer-shaped head &
receives regurgitated liquid from a minor worker

Matthews & Matthews, 2010

Contd..
c.

Poised to defend :- Assassin bug & Shield bugs continuously watches her emerging

nymphs to

defend her predator

d. Formidable mother :-

The praying mantis Oxyophthalmellus spp. positioned

herself at base of a

twig to intercept the predators

e. Egg dumping or brood mixing :- Spatial proximity leads to brood mixing & alloparental care

communal breeding, egg dumping (lace bug) ,take-over of nests & offspring
burying beetle

is seen in case of

(Smith et al., 2012)

Contd..
4. Nest building & Burrowing

1. Deceiving enemies :- A bombyliid bee fly, Parasitoid of solitary wasp larvae lay several
eggs into the fake nest entrance made by the wasp

2. Hiding the evidence:- Synchronous motions of the front tarsi , rake the sand & producing a
characteristic pattern which hide its actual nest eg:-Bembix sand wasps

Contd..

4. Brooding behavior & viviparity

An alternative form of protection is to carry eggs or young either internally or externally

(Kolliker et al., 2013)

Contd..

2013 The Royal Entomological Society, Ecological Entomology, 38, 123137

FEMALE VS. MALE CARE

Parental care is indication of higher evolution

Types of care provided by either of the parent vary with the insect to insects
Dermapterans guard their egg until they hatch & cockroaches carry them in protective ootheca

(Costa, 2006)

MATERNAL CARE
o Maternal care is most exclusive form of parental care
o Damsel bug is a fearsome enemy of Lace bug , if given a chance will devour every last
nymph ,such case she diverts enemy by fanning her wings and climbing on its back

o Also guide the nymphs to an ideal leaf by blocking a branch which they mistakenly follow,
all too often she dies in the attack
(Noldus et al., 1991)

Contd..
Tortoise beetle Acromis sparsa arrange themselves into a symmetrical ring around the

hatchlings & allow them to reach near food sources in round up manner
Harlequin stink bug Tectocoris spp. defends her eggs aggressively because she lays only one
batch & are her sole chance for reproductive success

(Ken Preston et al., 2010 )

Cont..

P physical (nest, burrow, gallery tunnel, brood ball, etc.); B behavioural (i.e. defence
display, guarding); C -chemical (defensive pheromone, aggregation pheromone, alarm
pheromone , antimicrobial substance )
(Goershon et al., 2001)

Contd..

Many insects raise their offspring on organic substrates where Microbes is serious threat to offspring
development and survival either by decomposing their food resources or by directly infecting the offspring

Objective: To test the maternal egg attendance in the European earwig has a function as a social defense against mold
infection
To see the effect of egg attendance on hatching success
To investigated the potential roles of egg grooming behavior and maternal transfer of chemicals on hatching

Contd..

Result & Discussion

Experiment 1: - Effects of maternal egg attendance with and without mold exposure on hatching success (A)
and mean hatchling body weight (B)
Effect of mold spore exposure on the duration of maternal egg grooming was made over the course of a 75-min
observation period

Control

Treated
B

Contd..
Parameter

Control
Egg attendance

Hatching success (Chi square)

Hatching success (%)
Body weight (Mg)

Treated

not attended

Egg attendance

138.08

130.21

59.85

80

50

75

1.68

1.78

1.57

not attended
55.34
7
1.98

Contd..
Experiment 2:- Effect of maternal presence on chemical compounds on egg surface
Change of total hydrocarbon quantities over time & total hydrocarbon quantities on
glass beads mingled into maternally attended clutches and unattended clutches

The major Chemical were identified as

heneicosane (C21H44), Z-9-tricosene
(C23H46), tricosane (C23H48), Z-12pentacosene (C25H50) & internal standard

n-octadecane (C18H38)

Contd..

1. Maternal egg attendance reduced the detrimental effects of spore exposure

2. Spore exposure significantly increased the duration of maternal grooming

3. Attendance lead to incorporation of chemical compounds (hydrocarbons)

on the eggs

PATERNAL CARE
Exclusive paternal care has evolved in 8 order of insects

Males can improve females mating success by providing pre-zygotic nuptial gifts & postzygotic offspring care

Two ways in which female choice promote the expression of arthropod paternal care
a) Enhanced Fecundity Hypothesis
b) Handicap Principle

(Tallamy et al., 2001)

Contd..

By M. Kolliker et.al., 2000

Although sexual selection and natural selection can favour paternal behaviour, a number of parameter can help to
determine which has dominated in due course of evolution
Trait

Sexual selection

Natural selection

Clutch number produced

Iteroparous (>1)

Semeplarous (1)

Mating opportunities

Many

Few

Care versus foraging

Care interferes with female foraging Care may or may not interfere with
female foraging

Female preference

Preference for guarding male

No preference for guarding male

Clutches guarded simultaneously

>1

Paternal selfishness

Males will guard unrelated eggs

Males will not guard unrelated eggs

Female
Male

Sex reversal role

After mating, receptive males perform
vigorous pumping

Females respond by climbing on the

males back

The male abruptly scrubs the females

hemelytra,
female repositions herself
and begins to lay eggs
After 5 minute, male temporary forcing
the female out of & begins a new bout of
vigorous pumping
This cycle continues until the females
total egg clutch is deposited on the
males back

Case study

Reversed sex roles in the giant water bug, Abedus sps.

Female water bugs abandon their eggs to males that proceed to care for them. What has caused
such an unusual behavior?
An egg-encumbered male is placed in an aquarium, highest number (97%) of the eggs will hatch

Does this high egg survival rate depend upon eggs being carried on the back of a live male water
bug? If so, why?
Removing egg pads from the backs of six males, Smith placed each egg pad in a separate
fingerbowl in the laboratory ,none of the eggs were survived

Was something about the male exoskeleton necessary to their development?

Smith killed egg-bearing males and left them with eggs intact , but these eggs also failed to hatch

So attachment to a healthy male essential for hatching. Why?

He noticed, male keep egg pad at or above the waters surface. Perhaps regular exposure to
atmospheric air is required for development
(Robert smith,1970)

Contd..

Reasons for paternity

Females always prefer males which were already guarding egg
of another female

Males

willing to guard more than one clutch to promote re-

mating

A male always
attractiveness

willing to guard unrelated eggs to enhance his

BIPARENTAL CARE
Dung beetle

Female attends the offspring until

they pupate
She cleans mold growth & applying
antimicrobial chemicals derived from
her sternal glands
Male helps to dig
compact the dung pat

the

nest

&

Food relocation to nests reduce the

predation risk
(Matthews & Matthews 2010)

PHYSIOLOGICAL MEASUREMENTS OF PARENTAL CARE

Mechanism of parental care By direct internal chemical signals (i.e.
hormones) and indirect external chemical signals (i.e. pheromone)
(Kolliker et al., 2007)

It influence maternal reproductive physiology and future reproduction

Contd..
Chemical signalling - important mode of communication between parent & offspring

Apis mellifera, larvae produce a brood pheromone that influences care behaviours of
workers

JH, regulate the trade-off between care for current offspring and the production of new

eggs/clutches

JH

(Mas et al., 2008)

Contd..

Hypothetical mechanism for maternal care regulation

JH

Age, Nutritional state & JH

(Scott & Panaitof 2004 )

Host manipulation for offspring care

1.

Hymenoipimesis spp

Plesiometa argyra

2.

Ichneumon eumerus

Maculina rebeli, a butterfly parasitize by wasp

(Delago et al., 2009)

Contd..
3.

Bee wolf (Egyptian digger asp) Philanthhus triangulam known as paralysis inducing wasp. Its venom
contains potent neurotoxin (Philathotoxin) that evoke neuromuscular paralysis Of Bee prey

(Delago et al., 2009)

Contd..
4.

Sphecid wasp Ampulex compressa

paracitising Periplanata americana

for egg laying

(Delago et al.,2009 )

COST & BENEFIT OF PARENTAL CARE

Parental investment benefits a current progeny at the expense of future reproductive
success

Protection of eggs is one of the most basic forms of parental care seen in many insects

(Clutton et al., 1991)

Contd.

QUANTIFYING THE COSTS AND BENEFITS OF PARENTAL CARE IN

FEMALE TREEHOPPERS
Case study
( ZINK et. al., 2003)

1. Benefit of egg guarding: increased hatching success

There is Correlation between the hatching success, offspring survival & total number of

0.0007

21.5 @ 0.23 Nymph/egg/day

No. of nymph

guarding days by female presented below

0.804

0.483

Contd..

Costs of egg guarding: decreased future reproduction

Early abandonment of eggs allowed females to increase the overall number of future broods

1.23

6.4

14.4
4.6

0.62

10.0

Means of the future number of broods initiated (A), the mean length of those future broods
(B), and the mean future guarding duration (C) for females abandoning versus remaining for

Contd..
Parameter

Control (Egg guarding female)

Treatment (Non egg guarding

female)

Hatching success (In terms of per female)

0.007 nymph/female

0.005 nymph/female

0.05 nymph /egg

0.03 nymph/egg

0.804 nymph /egg

0.483 nymph /egg

More i.e. 2.1

Less i.e. 1.02

(In terms of egg)

Survival of Hatchling
Presence of mutual friend ant
( After hatching)

Contd..
Cost

Benefits

Egg guarding represents an

investment in terms of time , energy
& reduced future fecundity
Opportunities for laying additional
clutches will be reduced

Egg guarding by adults acts to increase the

hatching success
Offspring survival in guarded clutch will
increase increase

The egg guarding in Publilia concava shown the positive linear relationship between guarding duration and
hatching success
Females that abandoned immediately after egg laying suffered a 50% reduction in hatching success

Effect of Parental Care on the Duration of Larval Development and Offspring

Survival in Nicrophorus mexicanus Matthews (Coleoptera: Silphidae)

By -Sofa et. al., 2011

Objective of study
1. To see the effect of parental presence on larval development
2.

Effect of parental manipulation of the food resources on offspring survival

3. To see the difference in number of adult emerges during different treatment

Result & Discussion

Differences in time development & number of adult emergence among the three experimental groups in N.
mexicanus 1.Control group; 2.Brood-mass present and parents removed; 3.Without parental care
(brood mass not present and parents removed).

13.14 +/- 0.45

11.40 +/-0.30
10.20 +/- 0.37

P<0.05

Contd..
The larval development required is 10.20 +/- 0.37 ,11.40 +/-0.30 &13.14 +/- 0.45
days respectively in Group 1,2 & 3
Survival of larva at L1 is 97%,95% &90% respectively
Treatment groups

Offspring
survival

Parameter

Ni

L1

L2

L3

1) Control: parental care

390

97

90

70

2) With Brood-mass. Parents removed prehatching

468

95

89

60

3) Without parental care : with fresh meat,

brood-mass no present and parents
removed pre-hatching

351

90

77

28

Contd.
Significant differences in the variation the number of offspring surviving to adult
emergence between three experimental groups
The number of adults that emerged was significantly different among the three
groups (X2 =11.96, df = 5, P , 0.05)

Compared
groups

Difference

1 Vs 3

28.13 12.78 = 15.35

3.214

1 Vs 2

28.13-25.93 = 2.2

0.47

2 Vs 3

25.93 -12.78 = 13.15

2.75

Contd.
Contd.
Larval development was significantly shorter in the control group

The presence of both parents and brood mass were required for larvae to reach adulthood

The differences is due to better nutritional quality of the food prepared by parents through
the oral and anal secretions

Case study 2

Maternal vibration induces synchronous hatching

in a sub- social burrower bug
By-Hiromi et al., 2012

Objective :-

To investigate the effect of mother presence on hatching synchrony

What effect does parental care have upon hatching of embryos?
To ascertain whether embryos hatch , in response to the vibrational signal of mother

Result & Discussion

Occurrence pattern of maternal vibration. Means +SD are shown for bouts/min from the start of vibration
generated by seven mothers.
Hatching was synchronous, passing through a fixed series of sequential steps
Hatching pattern of embryos exposed to the different treatments. Mean + SD are shown for the percentage of
hatched eggs at 5 min intervals for the first 90 min, and for 12 h and 24 h from the start of hatching.

47.8+/-17.4 bouts of vibration /min

13.7+/-1.4 bouts /min

 Schematic diagram showing artificial vibration. Coiled a rigid wire around an electrodynamics cordless motor
glued a dead mother touching a mature egg mass with mid-leg

92.0+/- 13.7

88.2 +/- 14.4

b

39.4+/- 22.2

80.8 +/- 17.6

Duration of hatching

Rate of vibration

At 1st minute

13.7+/-14.4 bouts of vibration /min

At 8th minute

47.8+/-17.4 bouts of vibration /min

At the end

39.1+/-13.8 bouts of vibration /min, Mother Starts trophic egg production

Duration of hatching

Hatching success in Control & treated group

After 12 hour

97.0 +/- 4.5% and 94.5 +/- 6.5% respectively

After 24 hour

97.0 +/- 4.5% and 96.0 +/- 3.5% respectively

Duration of hatching

Hatching success during artificial vibration

At 1st 15 minute

39.4+/- 22.2

After 90 minute

80.8 +/- 17.6

After 12 hour

88.2 +/- 14.4

After 24 hour

92.0+/- 13.7

 Parents regulate the hatching.

Mothers were observed to guarding the egg mass without feeding for 6 to7 days

Highly synchronous hatching begins at 8.7 +/- 1.4 , which corresponded to the peak of the
maternal vibration

CONCLUSION
Parental care have many adaptive advantage
for offspring
Synchronous hatching promote aggregation of
young-one
Large scale aggregation of offspring act as
cooperative defense

FUTURE PROSPECTS

Study of parental care behavior help in mass killing of insect by

locating the brood site

If it is a parasitoid of any insect pest ,we can colonies it by habitat

management to control the host species