SUSTAINING THE WORLD THROUGH SCIENCE AND TECHNOLOGY

Life History


The metamorphosis of planthoppers is simple (i.e., paurometabolous; egg, nymph, adult no pupal stage). Asexual reproduction is known for some delphacids, but it is extremely rare; sexual reproduction is the norm.  Generally, the entire life cycle (nymphal growth, adult feeding, courtship, mating, egg-laying) will take place on the host plant.  Many species are found on only one, or very few, host species (i.e., are monophagous or oligophagous); but the host relationships of many species are unknown or in need of confirmation, and it is desirable to record host plants whenever possible.  Courtship often includes substrate borne acoustic signals, which in most species is produced by a specialized membrane, the tymbal, in the first abdominal segments.  Eggs are inserted into host plant tissue and hatch in a few days (except when overwintering).  Immatures frequently sequester themselves in hidden situations frequently low on the host plant.  The period of time required to reach adulthood from the egg is about 30 days, although this depends on environmental conditions, with more rapid maturation occurring in warmer temperatures (to an upper limit) assuming food and moisture requirements are met. 


Planthoppers may disperse as adults, or may remain on the host, depending partly host plant quality, time of season, and planthopper population levels.  Some species, such as the rice brown planthopper, are known to migrate long distances.  Many delphacid species have multiple generations a year.  Most species overwinter as eggs, but some a nymphs or adults.  Life history specifics vary geographically within a species, and it is not uncommon for a species to have a single generation per year in the north, but more than one generation per year in the southern parts of their range.

As part of courtship, adult planthoppers may produce substrate-borne vibrations using a membrane at the base of their abdomen called a tymbal.  These signals are species specific.  The same structure is the sound-producing organ of cicadas.  Some adult planthoppers augment the vibrations produced by the tymbal by tapping with their abdomen or by other, unknown, mechanisms. 

Ant-attendance of delphacids is uncommon, and should be documented when found.

Food
Delphacids are all plant feeders and are generally referred to as “phloem feeders” (some researchers on feeding behavior would offer more specific details). Most planthopper species feed on a single (or few) plant species insofar as known, although some feed on many plant species. Most delphacids feed on monocots (grasses, sedges, rushes) in damp situations, but others (e.g., Stobaera, Pissonotus, and many Hawaiian taxa) feed on dicots. Generally, the most advanced delphacid lineages are grass-feeders, which were derived from non-grass feeding ancestors. A compiled list of all known confirmed or reported delphacid hosts will be provided elsewhere on this site.*

*Temporarily, this information will be placed here. A draft listing of delphacid host plant records (pdf format) is here: (draft host plant use).  Some summary statistics of delphacid host use of higher plant groups is here (summary statistics).