An updated checklist of the Thysanoptera of Panama with comments on host associations

: An updated biological catalogue of the Thysanoptera of Panama is presented. As a result the new checklist presented here records 246 species, 87 of which were collected during a recent survey.


Introduction
Tropical forests play a fundamental role in key ecosystems processes, affecting the dynamics of regional and global climates. In addition, tropical ecosystems are reputed to support most of the world's biodiversity: almost countless species of animals and plants, a large number of which are still unknown. Less still is known about the complex web of interactions that weave these species into ecological communities. Thus, tropical forests represent one of the last great frontiers of biological exploration to which increasing numbers of scientists are flocking. Rates of tropical forest habitat degradation and destruction are higher than in almost any other biome and we are in danger of losing the vast majority of species before we have documented them (Lawton and May 1995). In comparison with most temperate ecosystems, Panamanian tropical ecosystems are characterized by extraordinarily high but poorly inventoried insect diversity, and by an absence of basic biological and ecological information (Godfray et al. 1999;Novotny et al. 2002). Information on the Neotropical species of the insect Order Thysanoptera is widely scattered (Mound and Marullo 1996). Here we attempt to summarize the available information concerning the biodiversity of these insects in Panama.
Thrips are particularly diverse in the tropics, and the species known from the Republic of Panama were first listed by Mound and Palmer (1992). That list included 175 species together with a historical review of the Thysanoptera. Also included was information on bionomics, distribution and a discussion of problems associated with the effective sampling of this group of insects in the field (Hood 1934;Mound and Palmer 1992;Bournier 1993;Mound and Marullo 1996;Sanchez-Monge et al. 2011). Laurence Mound has published extensively on the taxonomy of the Thysanoptera worldwide and has been at the forefront of developing our understanding of the phylogenetic, and hence systematic, relationships within the Thysanoptera (Mound and Palmer 1983;; Sampling sites ( Figure 1). Agroecosystems: the sites selected varied from dry areas in Panama (Arco Seco, provinces of Herrera, Los Santos, Coclé, Veraguas and west area of Panama Province) to the humid regions of Chiriquí Province (Boquete), Bocas del Toro and Darien. Natural habitats: two sites were selected for general survey, Barro Colorado Island (BCI) and Pipeline Road. At 09°6'11" N, 79°50'48" W, BCI is a 1500-ha island in an artificial lake, created during construction of the Panama Canal in the early 1900s. Mean monthly temperature is 26°C with a maximum of 27°C in April. Annual rainfall averages 2600 mm. The dry season often begins in December and ends in April or May. Median rainfall between January and March is 84 mm. A more extensive description of the site can be found in Croat (1978), Windsor (1990) and Leigh et al. (1996). BCI is covered by a semi-deciduous tropical moist forest (Holdridge et al. 1971). The southern and western parts of the island are old forest (>400 y) whereas the remaining area is younger forest (100 y) with small clearings near the laboratory buildings. We chose a 3500m transect to sample in the different environments on the island. Flowers were collected at least 2 m on each side of trails, making the total study area include > 1.4 ha. Pipeline Road is part of the 22,000-ha Parque Nacional Soberania (09°05'17" N, 79°35'51" W) located along the eastern side of Gatun Lake as close as 2 km from BCI. Average rainfall is higher than on BCI because the road runs in a south to north direction toward the Caribbean coast, which receives 3500 mm annual rainfall. We worked along km 4 to 10 on Pipe Road Line and near the town of Gamboa, for a minimum area of 2.8 ha. The park is composed of mature lowland forest with some roadside covered by 60-70-y old secondary forest. Secondary forest and disturbed habitat were more strongly represented here than on BCI. Transects were walked from early morning to early afternoon (BCI) or until late afternoon (PR). All the plants were identified with specialized botanical dichotomous keys and the names were checked in the IPNI database and The Plant List, a working list of all plant species (http:// www.theplantlist.org/).
In general, thrips are most easily collected by beating flowers and vegetation, also dead branches and dead leaves, over a small plastic tray (see: http://anic.ento. csiro.au/thrips/). Thrips were killed in 60% ethanol and mounted on microscopic slides using Canada balsam. The tarsal arolium of thrips adheres to the surface whilst any excess of rubbish is blown away. The beating process is laborious but is the only way to collect thrips from individual leaves and flowers, and thus be more certain of their host association. For more details about collecting techniques and specimens preparation see Mound and Walker (1982; and Mound and Marullo (1996). Samples were carried out in July 1998 from different climatic areas of Panama, including the tropical area of Darien and Chiriqui composed of primary rain forest and cloud forest, and the dry area of Arco Seco, predominated by huge horticultural areas of rice, sugar and watermelon crops.
The catalogue is arranged systematically under families and the two largest families are each divided into two subfamilies. Genera are listed alphabetically within each family or subfamily. New records are indicated by an *. New information for the species previously collected in Panama by other scientists (sampling data) is also provided. Information on biological aspects of some thrips is given when avalaible. We considered as potential host plants those on which both sexes of thrips were collected, with larvae in the majority of the cases. It is not possible to be sure that these larvae correspond to the adults with morphological studies only, but it is a first step to try to identify feeding associations. In Table 1 we present data on the thrips collected in Agroecosystems and natural habitats. This checklist is based on our sampling (more than 10,000 slides have been made after the survey), together with published records. Nomenclature follows that is used in a web-based world checklist (Mound 2012) and all thrips collected during the present study were certified with the collection of Thysanoptera at  Darwin Center of the Department of Entomology (The Natural History Museum, London). The studied material is deposited in the Insect Collection of the Basque Institute of Research and Development (Neiker) in Spain.

Aeolothrips microstriatus Hood, 1935.
This species is based on one male collected in Panama and cannot at present be placed satisfactorily into this genus (Mound and Marullo 1996). Feeding associations: probably predatory on small insects in flowers of trees. We collected it in Chiapas (Mexico) (Rocha et al. 2012) and Panama in flowers of Mangifera indica.

Frankliniella cephalica (Crawford DL, 1910).
Widespread in the Caribbean as well as from most of the mainland countries between Mexico and Colombia (Mound and Marullo 1996).

*Frankliniella cotobrusensis Retana and Mound, 1995.
We have found 32 females. Feeding associations: Unknown. Collected at montane sites in Panama. Retana and Mound (1995) collected at two montane sites in Costa Rica.

*Frankliniella curta Hood, 1942.
We have collected 15 females and 1 male. Feeding associations: apparently widespread in a variety of flowers of the Compositae. Accordingly, we have found it repeatedly in Heterocondylus vitalbae flowers.

Frankliniella floydandrei Sakimura and O'Neill, 1979.
Only the holotype female of this species collected near the Panama Canal is known (Mound and Marullo 1996).  Mound and Marullo (1996) recorded Ipomoea flowers and leaves (Convolvulaceae) as a host plant in Costa Rica.

Frankliniella invasor Sakimura, 1972.
This species was collected from Schawartzia simplex and Pseudobombax flowers in Barro Colorado Island (Mound and Marullo 1996). Sampling data: 570 females and 83 males. Feeding associations: This species was described on Acacia glauca flowers from Hawaii. Mound and Marullo (1996) recorded both sexes in flowers of Pseudobombax (Bombaceae) in Panama and in Allophylus occidentalis (Sapindaceae) in Costa Rica. We have found females and males in Pseudobombax septenatum, Jacaranda copaia, Tabebuia rosea (Bignoniaceae), Mangifera indica (Anacardiaceae) and Cordia alliodora (Boraginaceae).  Frankliniella minuta (Moulton, 1907). Widespread in Central America (Mound and Marullo 1996), it is usually a montane species, living in the flowers of various Compositae. Sampling data: 14 females and 3 males in montane areas. Feeding associations: We have found isolated specimens in Compositae plants.

*Frankliniella vargasi Retana and Mound, 1995.
We have collected 122 females and 16 males throughout Panama. Feeding associations: Mound and Marullo (1996) stated that this species is only known from a single female collected in Panama. We have collected both sexes in flowers of Clibadium surinamense and Tridax procumbens (Compositae).

*Frankliniella varipes Moulton, 1933.
We have collected four females in the montane areas of Chiriqui province. Feeding associations: Mound and Marullo (1996) collected isolated females from Miconia longifolia, Impatiens balsamina (Balsaminaceae) and Eschweilera (Lecythidaceae) flowers in Costa Rica. Unfortunately we did not find both sexes in Panama. Hood, 1915. New records: 314 females and 64 males in different crops throughout Panama. Feeding associations: Restricted to Zea mays and commonly found on fresh green leaves of young plants of this crop (Mound and Marullo 1996). We have also collected both sexes in grasses and young leaves of water and honey melon plants. Hood, 1925. Sampling data. Barro Colorado Island, 3/IV/1996, Maripa panamensis, 1 female; Clibadium surinamense, 1 male. Feeding associations: Mound and Marullo (1996) collected both sexes in Miconia flowers (Melastomataceae).

*Thrips simplex (Morison, 1930).
We have collected 18 females and 1 male in ornamental flowers of Chiriqui Province. Feeding associations: This species is a pest of cultivated Gladiolus, although populations can also be found on other Liliaceae. Mound and Marullo (1996) collected both sexes in flowers of Neomarica gracilis (Iridaceae). We have found females in Hippeastrum (Amaryllidaceae).

*Thrips tabaci Lindeman, 1889.
New records: 80 females have been collected in different crops. Feeding associations: It is highly polyphagous and is also a vector of tomato spotted wilt virus, but at times it is probably also predatory on suitable small sized arthropods (Mound and Teulon 1994).

*Tylothrips osborni
Two hundred and fifty six species have been collected and named up till now in Panama. From this compilation, throughout the sampling we have added 87 new-recorded species from Panama (these species are marked with an asterisk in the species checklist). The diversity of a thrips fauna is presumably related, in some way, to the diversity of the local flora and the range of niches this provides. Almost 9000 species of plants are known from Panama, 1222 are endemics and 7778 are shared with other countries (World Conservation Monitoring Centre www.wcmc.org.uk). Burger (1985) points out that many tree and plant species have considerably geographic ranges. Similarly, Lellinger (1985) indicates that only 12 of the 687 pteridophytes known from Panama are endemic, and that both Peru and Mexico have more than 40% of their known species in common with Panama and the larger Caribbean Islands more than 30%. The flora of the isthmus and its associated insects seem to be derived more through immigration from north and south than from local speciation, and this conclusion applies equally to the Thysanoptera (Mound and Marullo 1996). The winds, especially hurricanes reach the isthmus infrequently but they commonly move widely along the Caribbean island. This could be the mechanism of movement of many insects, including some pest thrips, to spread from one country to another in the Central America and the Caribbean Areas. Thrips palmi has been recently introduced in Panama, and it is very common in crops of honey and watermelon and in oriental vegetables. Three years ago was introduced in Costa Rica throughout the border of Bocas del Toro, probably for the illegal introduction of fruits (Goldarazena unpublished).
There is a group of about 45 species that have been widely introduced around the world, including many pests as well as many species associated with fungi on dead branches (Mound 1983). For example Merothrips floridensis or Tylothrips osborni (Table 1) are fungus-feeding species that were probably transported many years ago on sailing ships, in association with straw and palm fronds used as fodder and bedding (Mound 1983). Bananas and orchids are transported as planting material, and their thrips pests go with them. International trade market of flowers (Roses) and vegetables (lettuce and strawberries), have introduced The Western Flower Thrips, Frankliniella occidentalis, in Chiriqui Province. Many of this species are collected in Panama in the Agroecosystems (Table 1). The thrips fauna in the crops is much monotonous than in the natural ecosystems.
Distribution of thrips species within Panama, both in space and time, is affected by the altitude and seasons. Similarly, there seem to be considerable differences in the thrips fauna between sites with different rainfall patterns, and at different altitudes. Thrips seem to be least common in rainy season (May to November) and more abundant during dry season (mid December to April). Frankliniella panamensis and F. fallaciosa are quite common species at altitudes of 1400 m or more in the Volcan Barú area, but they are rarely found at lower altitudes. Elaphrothrips species are also rarely taken at altitudes of 1200 m on montane areas of Chiriqui Province, although they are abundant at lower altitudes on dead leaves. Our results are coincident with the studies that were carried out in Costa Rica (Mound and Marullo 1996).
Thrips species vary greatly in their degree of host specificity. Few species seem to be strictly monophagous. From the point of view of conservation of species this could be take into account, especially if the endemic plants are threatened by extinction for transformation of the tropical ecosystems (due to climatic change, use of the land etc). Fungus feeding thrips populations (Idolothripinae and some Phlaeothripinae) often show considerable spatial aggregation (Mound and Teulon 1994). Sampling repeatedly such species, with populations that are widely dispersed but locally aggregated could be led into local extinctions.