Ophryocystis elektroscirrha
Encyclopedia
Ophryocystis elektroscirrha is an obligate
, neogregarine protozoan that infects Monarch
(Danaus plexippus) and Queen
(Danaus gilippus) Butterflies. There are no other known hosts. The species was first discovered in Florida, around the late 1960s. Since then, it has been found in every Monarch population examined to date, including Monarchs sampled in North America, Hawaii, Australia, Cuba, and Central and South America.
Dormant spores occur on the cuticle
s of butterflies, in between the butterfly
's scales
. They are small, brown or black objects about 1/100th the width of a butterfly scale.
plant of Monarchs and Queens, during oviposition
(egg laying). Milkweeds contains toxins that partially protect Monarch larvae. The spores are ingested by the larvae. After they enter a host's gut
, the spores open and emerging sporozoites penetrate a larva's gut wall and migrate to its hypoderm
(the layer of cells that secrete the larva's cuticle), where they undergo two phases of vegetative reproduction
. After the caterpillar pupates, O. elektroscirrha starts reproducing sexually
. Three days before adults emerge, developing parasite spores can be seen through their pupal integuments. The adult butterflies emerge covered with spores, mostly on their abdomens. Parasites do not continue to replicate on adult butterflies and spores must be eaten by larvae before they can cause new infections.
, although they may be less active than uninfected females. Researchers have also shown that infected Monarchs have lower flight performance (shorter duration of active flight and lower flight speeds) than uninfected butterflies.
Obligate parasite
An obligate parasite is a parasitic organism that cannot complete its life cycle without dependence on its host.-See also:*Obligate intracellular parasite*Parasitism*Parasitic plant*Facultative parasite...
, neogregarine protozoan that infects Monarch
Monarch butterfly
The Monarch butterfly is a milkweed butterfly , in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer...
(Danaus plexippus) and Queen
Queen (butterfly)
The Queen Butterfly is a North and South American butterfly in the family Nymphalidae with a wingspan of 2.75–3.25" . It is orange or brown with black wing borders and small white forewing spots on its dorsal wing surface, and reddish ventral wing surface fairly similar to the dorsal surface...
(Danaus gilippus) Butterflies. There are no other known hosts. The species was first discovered in Florida, around the late 1960s. Since then, it has been found in every Monarch population examined to date, including Monarchs sampled in North America, Hawaii, Australia, Cuba, and Central and South America.
Dormant spores occur on the cuticle
Exoskeleton
An exoskeleton is the external skeleton that supports and protects an animal's body, in contrast to the internal skeleton of, for example, a human. In popular usage, some of the larger kinds of exoskeletons are known as "shells". Examples of exoskeleton animals include insects such as grasshoppers...
s of butterflies, in between the butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
's scales
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
. They are small, brown or black objects about 1/100th the width of a butterfly scale.
Life cycle
Ophryocystis elektroscirrha is usually transmitted from females to their offspring when the females scatter spores on their egg chorions and surfaces of milkweed leaves, the hostHost (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
plant of Monarchs and Queens, during oviposition
Oviposition
Oviposition is the process of laying eggs by oviparous animals.Some arthropods, for example, lay their eggs with an organ called the ovipositor.Fish , amphibians, reptiles, birds and monetremata also lay eggs....
(egg laying). Milkweeds contains toxins that partially protect Monarch larvae. The spores are ingested by the larvae. After they enter a host's gut
Gut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
, the spores open and emerging sporozoites penetrate a larva's gut wall and migrate to its hypoderm
Hypodermis
The hypodermis, also called the hypoderm, subcutaneous tissue, or superficial fascia is the lowermost layer of the integumentary system in vertebrates. Types of cells that are found in the hypodermis are fibroblasts, adipose cells, and macrophages...
(the layer of cells that secrete the larva's cuticle), where they undergo two phases of vegetative reproduction
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
. After the caterpillar pupates, O. elektroscirrha starts reproducing sexually
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
. Three days before adults emerge, developing parasite spores can be seen through their pupal integuments. The adult butterflies emerge covered with spores, mostly on their abdomens. Parasites do not continue to replicate on adult butterflies and spores must be eaten by larvae before they can cause new infections.
Effect on individual butterflies
Because O. elektroscirrha is geographically widespread, it may have a long history of occurrence with Monarch Butterflies. Nevertheless, infection by O. elektroscirrha can cause a range of lethal and sublethal effects, and parasitized Monarchs have lower survival before adulthood, smaller adult body size, and shorter adult lifespans. Studies designed to test the negative effects of O. elektroscirrha on Monarch fitness showed that this parasite's effects are more severe when Monarchs ingest a higher initial dose of spores, and further depend on the larval instar (age) at inoculation, with animals infected at earlier instars suffering more from their infections. Adult Monarchs that emerge with high spore densities have decreased eclosion (emergence from pupae) success, smaller wingspans, and lower body masses than uninfected adults. Although Monarch mating success decreases with higher parasite loads, females that survive long enough to mate and initiate egg production to not appear to experience a significant decline in lifetime fecundityFecundity
Fecundity, derived from the word fecund, generally refers to the ability to reproduce. In demography, fecundity is the potential reproductive capacity of an individual or population. In biology, the definition is more equivalent to fertility, or the actual reproductive rate of an organism or...
, although they may be less active than uninfected females. Researchers have also shown that infected Monarchs have lower flight performance (shorter duration of active flight and lower flight speeds) than uninfected butterflies.