Geographic Range
Triatoma sanguisuga
is found in the southeastern United States and throughout Latin America. This range
includes both the Nearctic and Neotropical regions. It occupies North America in a
range stretching from Pennsylvania to Florida and as far west as Arizona. Most research
on this insect is performed only with regard to the United States, so an exact range
in Latin American is unknown.
- Biogeographic Regions
- nearctic
- neotropical
Habitat
Triatoma sanguisuga
is found in terrestrial and wooded environments where small mammals live.
Wood rats
are the most common host for these blood sucking insects, and the rat nests provide
a convenient home for the insects. Large flat rocks, detritus, and wood piles provide
structural support for the rat nests and safety for the insects because they can feed,
digest, and lay their eggs within.
Triatoma sanguisuga
also nests in human residences or farms when utilizing other animal sources of blood.
It can be found under loose wooden floorboards and older building structures.
- Habitat Regions
- temperate
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- Other Habitat Features
- urban
- suburban
- agricultural
Physical Description
Triatoma sanguisuga is on average 22 mm long and exhibits bilateral symmetry. It has an oval-shaped black body with red stripes on the outer edge of its thorax that continue onto its abdomen. Its two rear legs are twice as long as its four front legs. Its narrow head projects from its body, with large eyes protruding from half-way. T. sanguisuga has a significant proboscis on its head that is used to enter the blood vessel of its host during feeding. Jointed antennae also project from mid-way on the head. The sensory organs on the antennae, called sensilla, exhibit one example of sexual dimorphism in T. sanguisuga , where males have a higher density and different patterns than females. Nymphal instars are morphologically similar to adults, except they lack wings and their heads are slightly smaller. Eggs are small, white ovals measuring between 1 to 2 mm.
Different populations of the insect are influenced by different geographical barriers
- and consequently, multiple haplotypes and physical characteristics have developed.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- polymorphic
- Sexual Dimorphism
- sexes colored or patterned differently
Development
These insects are hemimetabolous, and have incomplete metamorphosis. Life stages include
the egg, nymph (instars), and adult. The eggs of
Triatoma sanguisuga
are deposited once the female has been fertilized and has received a blood meal.
During embryonic development, a higher environmental temperature speeds development.
A nymphal instar finds a blood meal 2 to 3 days after hatching. During the nymphal
stage,
T. sanguisuga
undergoes ecdysis, which is repeated cycles of shedding. After sufficient feeding
and digestion time, the molting hormone is released which signals the nymphal instar
to molt. If born early in the warm season, a nymph can complete five instar stages,
each separated by a molt. It undergoes hibernation during the winter months, during
which it remains in an awakened sluggish state. The remaining nymphal stages are completed
the following year if not completed in the first summer season. After completing 8
nymphal instar stages, the insect is considered to be an adult.
- Development - Life Cycle
- metamorphosis
Reproduction
Females and males are polygynandrous; each sex finds multiple mates during their lifespan.
Shorter in comparison to related insects, the mating time of
T. sanguisuga
lasts only 10 minutes. After male fertilization, females migrate to a new territory
to found a new community.
- Mating System
- polygynandrous (promiscuous)
A female develops eggs in her ovarioles, but does not deposit them until she has been
fertilized and has received a blood meal. Depending on host preference, space availability,
and season of sexual maturity, a female can lay hundreds of eggs during her life.
More eggs are laid when ambient temperatures are higher. Eggs are laid between May
and September in the northern hemisphere. They are deposited individually while the
female digests her most recent blood meal. Unfertilized eggs remain in the ovarioles
of females for the rest of their lives.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
Adults of
Triatoma sanguisuga
do not provide any parental care other than provisioning of eggs. Each yolk provides
nutrients for the fertilized eggs. Females do not take care to lay eggs in any specific
place, but instead, they are laid where the females digest their last blood meal.
- Parental Investment
-
pre-hatching/birth
-
provisioning
- female
-
provisioning
Lifespan/Longevity
In a laboratory setting,
Triatoma sanguisuga
is found to live for 450 days on average. However, in this experiment, the insects
did not undergo hibernation phases. Consequently, in nature its life cycle would be
approximately 3 years when including the hibernation periods.
T. sanguisuga
is able to survive for long periods on relatively few feedings, with lab populations
living over 100 days on only three or four meals.
Behavior
Triatoma sanguisuga lives in colonies. Information regarding the number of individuals living in a colony was unavailable, however these colonies are typically founded by one female and her newest brood of eggs. Triatoma sanguisuga is active during the warmer months, hibernating through winter from late November to early March. The saliva it secretes during a bite functions as an anesthetic, allowing T. sanguisuga to feed for 3 to 8 minutes without alarming its host, which is usually sleeping. Whenever possible, it chooses to feed during the night and then hang upside down while digesting the blood meal. While nymphs avoid light, the adults are attracted to it, and use this sense to locate hosts.
After
T. sanguisuga
begins feeding, molting hormones are released into its blood stream and initiate
its molting phase. However, if not given adequate time to feed and secrete these hormones,
molting is disrupted and incomplete. Other behaviors characteristic to
T. sanguisuga
include the defecation schedule following feedings. First, it empties its fecal pouch
following a feeding. Later, it defecates a large amount of excess liquid from the
recent blood meal. Finally, it defecates a large quantity of hemoglobin. The protozoa
Trypanosoma cruzi
, which causes Chagas disease, is sometimes present in the feces of
T. sanguisuga
, but because
T. sanguisuga
does not defecate immediately and while still located on its host, it is not as significant
a vector of
Trypanosoma cruzi
as other related species.
Home Range
These insects have a small home range. Since they live in the nests of their hosts,
they have little need to travel away from their homes. This convenience allows them
to be relatively sedentary and to live in colonies.
Communication and Perception
Triatoma sanguisuga
, like other
Triatomine bugs
, uses a variety of sensory modalities to locate its prey. It detects carbon dioxide
levels, host-specific odors, moisture gradients, heat, and air flow messages. Some
hosts emit specific chemical cues or infrared radiation that it can follow as well.
Most
Triatoma
species posses segmented antennae bearing sensing bristles called sensilla. The arrangement
and morphology of the sensilla varies, but in general, they function as the organs
for chemoreception. The sensilla density and patterns exhibit sexual dimorphism, also
suggesting a role in reproduction sensation.
Triatoma sanguisuga
has several ways to find hosts. It detects carbon dioxide levels, specific host smells,
changes in moisture, heat, and changes in air flow. Some hosts produce specific chemicals
or infrared radiation that
T. sanguisuga
can follow. Most
Triatoma
species have antennae with special bristles called sensilla. These sensilla are organs
that detect chemicals. Since the pattern and amount of sensilla is different between
males and females, they probably play a part in sensing a mate during reproduction.
- Other Communication Modes
- pheromones
- Perception Channels
- visual
- infrared/heat
- tactile
- acoustic
- chemical
Food Habits
Triatoma sanguisuga
derives its name from its only food choice, blood meals. It typically lives within
the nests of its host, so that a food source is always near. Its most common host
is the wood rat,
Neotoma floridana
, but it is also known to bite
humans
,
horses
, and other small mammals.
- Primary Diet
- carnivore
- Animal Foods
- blood
Predation
Little information is available about animals that prey on Triatoma sanguisuga .
Ecosystem Roles
Triatoma sanguisuga
is an obligate parasite that requires blood to complete its life cycle. It uses its
proboscis to feed on blood from hosts that include
eastern wood rats
,
horses
,
humans
, and other small mammals such as
raccoons
and
armadillos
. While the bite made for feeding can go unnoticed, due to anesthetic in its saliva,
a bite made in self-defense is painful and can cause swelling, dizziness, or nausea.
Triatoma sanguisuga
can act as a vector for
Trypanosoma cruzi
, a protozoan that causes Chagas disease, or viruses that cause equine enchephelomyelitis.
Both of these pathogens can be fatal for the host. However, the defecation behavior
of
T. sanguisuga
limit its risk of causing infection, as it does not defecate immediately while still
on its host.
- Ecosystem Impact
- parasite
Economic Importance for Humans: Positive
There are no known positive effects of Triatoma sanguisuga on humans.
Economic Importance for Humans: Negative
Triatoma sanguisuga
has been increasingly threatening to humans. Its primary nuisance is its blood feedings.
It is also called the Mexican bed bug because it is known to feed at night. A third
common name, the kissing bug, is earned because it tends to bite around the eyes and
lips. In addition to the bite,
T. sanguisuga
is a confirmed vector for
T. cruzi
, a parasitic trypanosome that causes Chagas disease. The bite alone does not confer
the parasite, but itching and allowing
T. sanguisuga
fecal material to enter the skin completes the transmission. Chagas disease is a
serious and potentially lifelong disease, that at first can cause fever and swelling,
and later can cause serious life threatening symptoms such as heart complications.
This disease is most prevalent in Mexico, Central and South America, with as many
as 11 million people infected.
Triatoma sanguisuga
can also transmit the virus that causes equine encephalomyelitis.
- Negative Impacts
-
injures humans
- bites or stings
- carries human disease
- causes or carries domestic animal disease
- household pest
Conservation Status
Triatoma sanguisuga
has no special conversation status and is in no danger of extinction. The population
is under control guidelines due to its role as a vector of
Trypanosoma cruzi
and consequential harm to humans.
Additional Links
Contributors
Laura Maurer (author), University of Michigan-Ann Arbor, Angela Miner (editor), Animal Diversity Web Staff.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polymorphic
-
"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.
- metamorphosis
-
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- nocturnal
-
active during the night
- parasite
-
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- hibernation
-
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
- colonial
-
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- pheromones
-
chemicals released into air or water that are detected by and responded to by other animals of the same species
- visual
-
uses sight to communicate
- infrared/heat
-
(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- parasite
-
an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death
- causes or carries domestic animal disease
-
either directly causes, or indirectly transmits, a disease to a domestic animal
- carnivore
-
an animal that mainly eats meat
- sanguivore
-
an animal that mainly eats blood
References
Borror, D., C. Triplehorn, N. Johnson. 1989. An Introduction to the study of Insects . Philadelphia, PA: Saunders College Publisher.
Catalá, S. 1997. Antennal sensilla of Triatominae ( Hemiptera , Reduviidae ): A comparative study of five genera. International Journal of Insect Morphology and Embryology , 26/2: 67-73.
Cesa, K., K. Caillouet, P. Dorn, D. Wesson. 2011. High Trypanosoma cruzi ( Kinetoplastida : Trypanosomatidae ) Prevalence in Triatoma sanguisuga ( Hemiptera : Redviidae ) in Southeastern Louisiana. Journal of Medical Entomology , 48/5: 1091-1094.
Dorn, P., L. Perniciaro, M. Yabsley, D. Roellig, G. Balsamo, J. Diaz, D. Wesson. 2007. Autochthonous Transmission of Trypanosoma cruzi , Louisiana. Emerging Infectious Diseases , 13/4: 605-607.
Drees, B., J. Jackman. 1999. "Kissing Bug, Conenose Bug, Masked Hunter" (On-line). AgriLIFE Extension. Accessed February 06, 2012 at http://insects.tamu.edu/fieldguide/aimg53.html .
Encyclopedia Britannica, 2012. Assassin Bug (insect). Pp. n/a in Encyclopædia Britannica Online , Vol. n/a, n/a Edition. n/a: n/a. Accessed March 24, 2012 at http://www.britannica.com/EBchecked/topic/39144/assassin-bug .
Grudemann, A. 1947. Studies on the Biology of Triatoma Sanguisuga in Kansas. The Journal of the Kansas Entomological Society , 20/3: 77-85. Accessed February 06, 2012 at http://www.k-state.edu/parasitology/articles/Triatoma-01.pdf .
Klotz, S., P. Dorn, J. Klotz, J. Pinnas, C. Weirauch, J. Kurtz, J. Schmidt. 2009. Feeding behavior of triatomines from the southwestern United States: An update on potential risk for transmission of Chagas disease. Acta Tropica , 111/2: 114-118.
Kobylinski, K., R. Connelly. 2009. "Blood Feeding Insect Series: American Trypanosomiasis - Chagas Disease" (On-line). University of Florida Department of Agriculture. Accessed February 06, 2012 at http://edis.ifas.ufl.edu/in650 .
Roden, A., D. Champagne, B. Forschler. 2011. Biogeography of Triatoma sanguisuga ( Hemiptera : Reduviidae ) on Two Barrier Islands off the Coast of Georgia, United States. Journal of Medical Entomology , 48/2: 806-812.
Stevens, L., P. Dom, J. Schmidt, J. Klotz, D. Lucero, S. Kotz. 2011. Kissing Bugs. The Vectors of Chagas. Advances in Parasitology , 75/na: 169-192.
Wild, A. 2012. "The Friendly Face of Triatoma Sanguisuga " (On-line image). Alex Wild Photography. Accessed February 06, 2012 at http://www.alexanderwild.com/Insects/Bountiful-Bugs/4191931_FWpfRM/1491542895_hmSJTS2#!i=1491542895&k=hmSJTS2 .
de la Rua, N., L. Stevens, P. Dorn. 2011. High genetic diversity in a single population of Triatoma sanguisuga inferred from two mitochondrial markers: Cytochrome b and 16S ribosomal DNA. Infection, Genetics and Evolution , 11/3: 671-677.
Integrated Taxonomic Information System. Triatoma Sanguisuga . n/a. US, Canada, and Mexico: Integrated Taxonomic Information System. 1996. Accessed February 06, 2012 at http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=107473 .
Centers for Disease Control. Parasites - American Trypanosomiasis (also known as Chagas Disease). n/a. Atlanta, Georgia: Center for Disease Control. 2010. Accessed February 06, 2012 at http://www.cdc.gov/parasites/chagas/gen_info/vectors/index.html .