Marisa Benjamin, Emily Michaeles, Kira Pearson
Bio-345 Animal Behavior
Background and Significance
Female choice is a behavior seen in many species of animals and is an important concept to understanding female aggression within female praying mantis. Males can fight over females as much as they want but in the end it’s the female who almost always will be the one who chooses the fittest male. Females will want to choose the best mate in order to increase her own fitness and she may choose based on many categories. The size of a male, color, sperm quality, the nuptial gifts they choose to give the female. A male may have one or all of these qualities in order to increase their chance of mating with a female. Another extreme form of female choice that is sometimes displayed is that of sexual cannibalism. Cannibalism in animal species is generally uncommon unless specific nutrients cannot be gained otherwise. Cannibalism can also be displayed in species that have overcrowded populations as a way to keep numbers steady. Consuming another member of the same or similar species is a good way of getting necessary nutrients and cutting down on future competition. Often, mothers will consume their young if they are born dead or too weak. This happens when the mother is under stress and needs to recover some nutrients after childbirth to be able to protect their other offspring. Differentiating between the need for females to cannibalize and an act of aggression will be important in this study.
Some of the most sexually cannibalistic animals are arachnids and scorpions and within these two groups, sexual cannibalism takes many forms regarding roles, behaviors, and benefits of each sex. In the fishing spider, females decision to cannibalize a male showing courtship depends on the males value as a meal, rather then his value as a mate. (Henriksson, 1997). In scorpions
Praying mantis sexual cannibalism is not as frequent as one might think only occurring about 13-28% of all mating events in nature (Barry, Brown, 2016). So more times than not the male praying mantis comes out of the mating alive and can continue on finding another female to mate with. For those males that do get eaten during intercourse, it’s usually by choice of the female however, the male also benefits from this behavior even though he loses his life and other chances to mate later on. When the female begins to consume the head of the male, the sperm transfer actually increase the amount of sperm given and shortens the length of time for the mating (Barry, Holwell, al, 2008). The now dead body of the male can also supply the female with up to 60% of her dietary needs during the mating season. Which in turn helps the fertilized eggs to more likely make it to birth ensuring the males offspring make it. This sexual cannibalism behavior seen by the females now raises the question does the levels of aggression of the female at the time of the mating determine if this behavior occurs?
Mantids are known for their aggressive behavior towards the same species, prey and predators alike. Praying Mantis are some of the top predator insects, preying on many sizes and species of insect and arthropods and even some larger vertebrates should the occasion arise. (Prete, Komito, 2011, pg.887). When at rest, praying mantis will hold their front two forelegs up in a praying like position. When attacking prey or other mantids, they use their forelegs to grab onto and subdue them. Each foreleg of the praying mantis has overlapping spines that grip into the prey, so then the mantid is able to hold long enough to bite through its neck, paralyzing it. Once paralyzed the praying mantis will slowly eat the prey from the head down (Pests.org).
The species of Praying mantis that will be used in this experiment is known commonly as the “Giant Asian Praying Mantis”, also known as Hierodula Membranacea. As the name suggests this Praying mantis originated in Asia and can commonly be found in any grassy environments where the climate is hot and humid. Like most other species of praying mantis they will eat any insect, praying mantis or vertebrates of any size, that come into their sight. This species is considered one of the most aggressive towards each other and other organisms, making them a good specimen to study aggression. Giant Asian Mantis can be multiple colors such as brown, yellow, beige, and even a pink like color, however green is the most common color seen. Females tend to be around three to five inches when fully grown and males around 3 inches (Linda, 2018).
- Objectives, Hypotheses and Predictions
Hypothesis: Female praying mantis will display aggressive behavior if they are in the presence of a male praying mantis
Prediction: If a female praying mantis are aggressive towards males (striking, rocking, or bluffing) then when presented with a male, the female will display these aggressive behaviors.
Praying Mantis acquired from Penterrapets.com. We will be receiving 12 mantises, six males, six females. They will be adult mantises and should arrive sometime during the week of March 19th.
For each of the 12 Praying Mantises we will have separate but identical clear plastic containers for each one. Within the containers we will lay damp leaves on the ground as a substrate. Mesh like fabric will be also supplied to hold the live prey, so the mantis are able to eat without the prey escaping. Other supplies such as rocks and sticks will also be included so the mantis can walk and climb. They will be kept in the greenhouse under daily observation to make sure they are alive and well. Heat Lamps will be provided and daily watering to insure humidity and temperature needs are met.
Given that females tend to show aggressive behavior we will observe the behavior of the female when put in different environmental conditions.
Praying Mantis Behaviors:
|Perceiving motion of prey||head is rapidly rotated to bring the object into the visual field of the fovea, motions of the prey are then tracked by movements of the mantis’s head so as to keep the image centered on the fovea|
|Camouflage||Does this behavior to hide from their prey also does this to hide from predators|
|Ambush Hunting||Remaining motionless for a long period of time, long arms ready to attack|
|Paralyzing||When mantis catch prey they bite the neck of its prey to paralyze it|
|Rocking||When they do move, they travel forward while gently rocking back and forth rhythmic, repetitive side-to-side movements, helps them to blend in with the bush or tree they are climbing on, as it sways in the breeze.|
|Feeling threatened||Standing tall and spread their forelegs, with their wings fanning out wide|
|Fanning of the wings||Makes the mantis seem larger and more threatening|
|Striking||Strikes with its forelegs and attempt to pinch or bite.|
|Bluffing||Produce a hissing sound by expelling air from the abdominal spiracles|
|Mate following Courtship||Male leaps onto the female’s back, clasping her thorax and wing bases with his forelegs. He then arches his abdomen to deposit and store sperm in a special chamber near the tip of the female’s abdomen|
|Molting||Molting can happen five to 10 times before the adult stage is reached|
|Sexual Cannibalism||They begin feeding by biting off the male’s head (as they do with regular prey), and if mating has begun, the male’s movements may become even more vigorous in its delivery of sperm|
|Courtship||The male engages the female in a courtship dance, to change her interest from feeding to mating.
The most common courtship is when the male approaches the female from the front, slowing the speed of his approach the closer he gets. The second most common courtship is a different approach, in which the male comes to the female from behind, speeding his approach the closer he gets. He will then jump on her back, they will mate, and he will fly away.
|Flashing colored eyespots||In response to male courtship, the female has been known to respond with a defensive deimatic display by flashing the colored eyespots on the inside of her front legs|
|Feeding||Blend right into a leaf or flower, waiting to strike. As soon as another insect comes close enough, the mantis will strike out it’s forelegs and catch it. will also almost always eat the insect starting from the neck, allowing the struggling to come to a quick halt.|
Condition 1: Control- Placing 1 female and 1 male in a separate container. Constructing an ethogram of all the behaviors shown in a time frame of 20 minutes.
Condition 2: Placing 1 female and 1 male in a separate container and then adding 1 cricket and observing behavior (looking to see if female behavior changes when a food source is added)
After testing these conditions to confirm the conception that female praying mantis are aggressive towards males, we will perform a chi squared analysis. This will tell us if female aggression is statistically significant and if there is a purpose behind our next experiment.
*****Females on low quality diets have a higher chance to engage in sexual cannibalism compared to females on high quality diets. Submissive males gain a selective advantage by producing offspring
- References Cited
Linda. “Giant Asian Mantis.” Giant Asian Mantis, 2018, http://www.keepinginsects.com/praying-mantis/species/giant-asian-mantis/.
Prokop, Pavol, and Michael R. Maxwell. “Female Predatory Response to Conspecific Males and Heterospecific Prey in the Praying Mantis Mantis Religiosa: Evidence for Discrimination of Conspecific Males.” SpringerLink, Springer Japan, 10 Feb. 2016, link.springer.com/article/10.1007/s10164-016-0458-8.
- Resources Required
- 12 Praying mantises
- 12 single containers that are twice as big as the body size
- Wooden Sticks
- Alive fruit flies
- Alive Micro crickets
- Spray bottle for water
- Leaves for the ground
- Mesh like fabric
- Paper towels for substrate
- Heat lamp
- One way window for bigger habitat
- Glass divider