Reproduction, Embryology and Development Flashcards
Name common ways in which a male and female insect find/attract each other for mating.
- On a host
- At a food source
- Through Lek behavior
- Visual displays
- Chemical attractants (pheromones)
- Sound Production
- Hill Topping behaviour
What is Lek Behavior?
When a male insect defends a territory on common mating ground in hopes of having a better chance of acquiring mates.
Why might insects meet and mate on a host? (example)
In Parasites such as strepsiptera, the females are wingless and attach themselves to a host with only their abdomen showing. the Males seek out the hosts in order to mate with the females.
Why/How might an insect meet at a food source. (example)
Face flies are attracted to cowpies by their olfactory emanations. the insects mate and the females oviposit on the cow pies.
In what insects are visual displays common?
Butterflies, fruit flies and fireflies
When are chemical attractants useful for locating a mate?
When a potential mate could be over a kilometer away.
What is hill topping behavior?
When males of a species fly up to and fight over the highest point of a hill in order to have the best chance of mating with a female.
What is courtship for insects?
Often a complex cascade or sequence of behaviors required for copulation to proceed.
What does copulation usually depend on?
Tactile stimulation, sometimes coupled with short-range chemical stimulation
What is a post-copulatory behavior in dragonflies?
A prolonged tandem flight (males stay attached to females) to insure that no additional males can mate with the “guarded” female
What is a post-copulatory behavior in some moths?
Male moths secrete substance from accessory gland during copulation which makes the female unreceptive to other males. May also inhibit secretion of sex attractant pheromones in the females.
What is a post-copulatory behavior in Orthoptera?
The males produce a genital plug that prevents other males from mating with the female
How does fertilization take place in the most primitive insects?
Through indirect sperm transfer.
-Males deposit a packet of sperm on the substrate which is later picked up by the female
What is indirect sperm transfer?
Males deposit a packet of sperm on the substrate which is later picked up by the female
How does fertilization take place in the higher orders of insects?
Internally
- Genitalia are often highly species specific and specialized to deliver spermatophores into the female reproductive tract. The sperm are stored in the female’s spermatheca until needed.
What is a spermatheca?
A pouch connected to the median oviduct which holds sperm in higher orders of insects
When and where does fertilization occur?
In the oviduct as the ova passes through it during ovulation.
How does fertilization take place in bedbugs?
Through direct hemocelic insemination
- Inject sperm through the integument of the female, anywhere on the body. some sperm migrate to ovaries, others are digested for energy
What is direct hemocelic insemination?
Male bedbugs Inject sperm through the integument of the female, anywhere on the body. some sperm migrate to ovaries, others are digested for energy
how do some male insects suppress the females feeding response in order to mate with them?
By bringing them gifts of food to occupy them
Why would a male insect bring a female a gift of food?
To suppress the females feeding response in order to mate with them
What is it called when Male bedbugs Inject sperm through the integument of the female, anywhere on the body. some sperm migrate to ovaries, others are digested for energy?
direct hemocelic insemination
What is the pouch connected to the median oviduct which holds sperm in higher orders of insects called?
spermatheca
What type of embryologic development do insects perform?
meroblastic (Partial cleavage)
Which structure undergoes nuclear cleavage during meroblastic development?
the zygote
What happens to the zygote during meroblastic development?
undergoes nuclear cleavage, producing daughter nuclei
What happens to the daughter nucleii of the zygote during meroblastic development?
they migrate to the outside of the egg and form a blastoderm
When is a blastoderm formed?
When the daughter nucleii of the zygote migrate to the outside of the egg
What is the primordium?
The thickened area that forms during meroblastic development that becomes the future embryo
What forms the mesoderm and endoderm during meroblastic development?
Invagination of the medial plate
What does the invagination of the medial plate during meroblastic development form?
the mesoderm and endoderm
How is the ectoderm formed during meroblastic development?
lateral plates fuse
What is formed when lateral plates fuse during meroblastic development?
the ectoderm
Invaginations during meroblastic development form what structures?
- The Stomodeum (Mouth)
2. The Proctodeum (Anus)
What is the Stomodeum?
the mouth
What is the Proctodeum?
the anus
What does the endoderm become?
the midgut
What does the Mesoderm become?
- musculature; body fat
- circulatory system
- gonads, lateral oviducts and vas deferens
What does the Ectoderm become?
- exoskeleton epidermis
- tracheal system
- nervous system
- foregut and hindgut (including malpighian tubules and excretory organs)
- medial oviduct, spermatheca and accessory glands
What must be shed at each molt?
the
- exoskeletal epidermis
- tracheal system
What is the rate of larval development influenced by?
Temperature and nutrition
What is the course of larval development determined by?
Hormonal factors
What are Ametabolous?
Larvae who only differ from their adult forms in size and development of gonads
What are Hemimetabolous?
Larvae who gradually change through seven instars and external wing development.
What are holometabolous
Larvae who differ from their adult forms by internal wing development and the formation of a pupa.
Larvae -> Pupa -> Adult
What is the major function of the pupa?
To allow change. permits the larvae to diverge totally from the adult from.
What makes having a larvae stage so advantageous?
The larvae and adult forms can occupy different niches. Also allows a high degree of specialization of life stages. (Larvae concerned with feeding, adults with mating etc)
What happens during the pupa stage?
The body is completely rebuilt. musculature is reabsorbed and replaced in the adult
What is the overwintering stage of the pupa?
A secondary function of the pupa in which the pupa can remain dormant for long periods and withstand environmental extremes.
How is the development of Tse tse flies different?
- Larvae are retained within the oviducts of the female.
- Females give birth to a single mature larvae that is dropped into the soil where it immediately pupates.
What does viviparous mean?
Give birth to a single mature larvae at pupates as soon as it is dropped onto soil
How is the development of Aphids different?
Aphids partake in an alternation of generations (discontinuous polymorphism)
- They may perform sexual reproduction (Maintains genetic diversity) or asexual reproduction (rapidly increase population growth)
