Sex is the trait that determines whether a sexually reproducing organism produces male or female gametes. During sexual reproduction, a male and a female gamete fuse to form a zygote, which develops into an offspring that inherits traits from each parent. By convention, organisms that produce smaller, more mobile gametes are called male, while organisms that produce produce larger, non-mobile gametes are called female. An organism, such as most flowering plants, that produces both types of gamete is a hermaphrodite.
Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the superfamily Coccoidea due to taxonomic uncertainties. Adult females typically have soft bodies and no limbs, and are concealed underneath domed scales, extruding quantities of wax for protection. Some species are hermaphroditic, with a combined ovotestis instead of separate ovaries and testes. Males, in the species where they occur, have legs and sometimes wings, and resemble small flies. Scale insects are herbivores, piercing plant tissues with their mouthparts and remaining in one place, feeding on sap. The excess fluid they imbibe is secreted as honeydew on which sooty mold tends to grow. The insects often have a mutualistic relationship with ants, which feed on the honeydew and protect them from predators. There are about 8,000 described species.
In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric.
Dioecy is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly or indirectly. Dioecious reproduction is biparental reproduction. Dioecy has costs, since only the female part of the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility.
Sequential hermaphroditism is one of the two types of hermaphroditism, the other type being simultaneous hermaphroditism. It occurs when the organism's sex changes at some point in its life. In particular, a sequential hermaphrodite produces eggs and sperm at different stages in life. Sequential hermaphroditism occurs in many fish, gastropods, and plants. Species that can undergo these changes do so as a normal event within their reproductive cycle, usually cued by either social structure or the achievement of a certain age or size. In some species of fish, sequential hermaphroditism is much more common than simultaneous hermaphroditism.
Male is the sex of an organism that produces the gamete known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilisation. A male organism cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually. Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs.
The Margarodidae or ground pearls are a family of scale insects within the superfamily Coccoidea. Members of the family include the Polish cochineal and Armenian cochineal and the original ground pearl genus, Margarodes. Beginning in 1880, a number of distinct subfamilies were recognized, with the giant coccids being the first. Although Maskell proposed a new family, many continued to regard the monophlebids as a mere subfamily for many years, and the Margarodidae classification continued to be polyphyletic through the 20th Century. Since then, taking the advice of Koteja several subfamilies and tribes have been elevated into their own families such as Matsucoccidae and Xylococcidae. The pared-down family of Margarodidae is monophyletic.
Icerya is a genus of scale insects in the family Monophlebidae. It is named after physician-naturalist Dr. Edmond Icery of British Mauritius.
Icerya purchasi is a scale insect that feeds on more than 80 families of woody plants, most notably on Citrus and Pittosporum. Originally described in 1878 from specimens collected in New Zealand as pests of kangaroo acacia and named by W.M. Maskell "after the Rev. Dr. Purchas who, [he] believe[d], first found it", it is now found worldwide where citrus crops are grown. The cottony cushion scale originates from Australia.
Theodore Dru Alison Cockerell (1866–1948) was an entomologist and systematic biologist who published nearly 4,000 papers, some of them only a few lines long. Cockerell's speciality was the insect order Hymenoptera, an area of study where he described specimens from the United States, the West Indies, Honduras, the Philippines, Africa, and Asia. Cockerell named at least 5,500 species and varieties of bees and almost 150 genera and subgenera, representing over a quarter of all species of bees known during his lifetime. In addition to his extensive studies of bees, he published papers on scale insects, slugs, moths, fish scales, fungi, roses and other flowers, mollusks, and a wide variety of other plants and animals.
Androdioecy is a reproductive system characterized by the coexistence of males and hermaphrodites. Androdioecy is rare in comparison with the other major reproductive systems: dioecy, gynodioecy and hermaphroditism. In animals, androdioecy has been considered a stepping stone in the transition from dioecy to hermaphroditism, and vice versa.
A hermaphrodite is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are of different sexes, either male or female but not both, are gonochoric, which is the opposite of hermaphroditic.
An organism's sex is female if it produces the ovum, the type of gamete that fuses with the male gamete during sexual reproduction.
Monophlebidae is a family of scale insects commonly known as the giant scales or monophlebids. They occur in most parts of the world but more genera are found in the tropics than elsewhere.
Wilmatte Porter Cockerell was an American entomologist and high school biology teacher who discovered and collected a large number of insect specimens and other organisms. She participated in numerous research and collecting field trips including the Cockerell-Mackie-Ogilvie expedition. She wrote several scientific articles in her own right, co-authored more with her husband, Theodore Dru Alison Cockerell, and assisted him with his prolific scientific output. She discovered and cultivated red sunflowers, eventually selling the seeds to commercial seed companies. Her husband and her entomological colleagues named a number of taxa in her honor.
Simultaneous hermaphroditism is one of the two types of hermaphroditism, the other type being sequential hermaphroditism. In this form of hermaphroditism an individual has sex organs of both sexes and can produce both gamete types even in the same breeding season.
Andromonoecy is a breeding system of plant species in which male and hermaphrodite flowers are on the same plant. It is a monomorphic sexual system comparable with monoecy, gynomonoecy and trimonoecy. Andromonoecy is frequent among genera with zygomorphic flowers, however it is overall rare and occurs in less than 2% of plant species. Nonetheless the breeding system has gained interest among biologists in the study of sex expression.
Gynomonoecy is defined as the presence of both female and hermaphrodite flowers on the same individual of a plant species. It is prevalent in Asteraceae but is poorly understood.
Monoecy is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contrasted with dioecy where individual plants produce cones or flowers of only one sex.
A sexual system is a pattern of sex allocation or a distribution of male and female function across organisms in a species. Terms like reproductive system and mating system have also been used as synonyms.
