lirSect Sei. Applic. Vol. 8. Nos 4/5/6. pp. 841-844. 1987 0191-9040!87 $3.00 + 0.00 Printcd in Great Britain. Ali rights reserved Ç' 1987 ICIPE-ICIPE Science Press IMPORTANCE OF TAXONOMY IN BIOLOGICAL CONTROL GILBERTO J. DE MORAES Centro de Pesquisa Agropecuraria do Tropico SemiArido (CPTSA):EMBRAPA. 56300-Petrolina. PE. Brazil (Received 27 .Vorember 1986) Abstrllct-Taxonomy is the starting poínt o f any basic or applied biological research. In biological control work, the pest species, its probable area o f origin. and. consequently. the location where promising natural enemies may be found. are identified. The dose co-operation o f taxonomists during pre- and post-release surveys of natural enemies in target arcas helps to indicate the indigenous fauna present and the progress of a biological control programme. Biological control programmes should budget for appropriate taxo­ nomic studies in areas where the local fauna is poorly known. Instructing local researchers on the correct collection, preservation, and identification of relevant indigenous and exotic species should be emphasized. Key Words: Taxonomy, classification. identification. biological control. biosystematics Réswné--La taxonomie est !e point de départ de toute recherche biologique fondamentale ou appliquée. Dans Ie cadre de Ia Iutte biologique, son étude permet. Iorsqu'elle est correctement menée, d'identifier Ies différentes espéces de ravageurs. leur Iieu d'origine éventuel et. par conséquent. les sites ou I'on a !e plus de chance de trouver des ennemis naturels prometteurs. La collaboration étroite des taxonomistes au cours des enquétes antérieures et ultérieures aux lâchers d'ennemis naturels dans les zones cibles permet d'évaluer la réussite du programme de lutte biologique. Dans Ies régions ou I'on posséde peu de données précises sur la faune locale, les programmes de Iutte biologique doivent prévoir dans leur budget une étude taxonomique. L'importance de la formation, au niveau local, de chercheurs aptes à identifier les especes indigénes et exotiques devrait être soulignée. Mots C/éfs: Taxonomie. classification, identification. Iutte biologique. biosystématique INTRODUCfiON co-operation between biological control specialists and taxonomists. The need for co-operation starts Taxonomy is the theory and practice of classifying with the proper identification of the target pest. organisms. The term classification has two different Incomplete or wrong identification of the pest may meanings: the product of the activity of the taxon­ lead to the wrong determination of its place o f origin. omist and the activity o f classifying, which consists o f where efficient natural enemies are expected to be ordering populations and groups ofpopulations (taxa) found. This can result in considerable amounts of at ali leveis by inductive procedures (Mayr, 1969). money and time spent without obtaining useful results. Identification consists of placing individuais into One of the best examples of the consequences of previously established taxa by deductive procedures. improper identification o f a pest species was a project This field of research is of utmost importance for for the biological control of the coffee mealybug in any area of basic and applied biology, and without it Kenya (LePelley, 1943; DeBach, 1974). This mealy­ scientific communication among biologists would be bug, Planococcus kenyae (LePelley), was first consi­ severely limited. dered to be the citrus mealybug, Pseudococcus citri Biological control specialists recognize the import­ (Risso), and !ater to be Pseudococcus li/acinus Ckll. ance of taxonomy as a starting point for the intro­ For this reason, 12 years were spent in exploration duction, conservation and augmentation of natural and introduction of the wrong natural enemies from enemies, as extensively discussed by severa! authors four continents. The ultimate success of this project (Ciausen, 1942; DeBach, 1974; Eickwort, 1983; was achieved after it was evident that the coffee Schlinger and Doutt, 1964; Smiley and Knutson, mealybug was a species distinct from P. /i/acinus, 1983). which led to the importation of Anagyrus sp. near The purpose of this paper is to show the relation kivuensis Compére from nearby Uganda: where P. between biological control work and taxonomy, the kenyae was present but rare. reasons for limitations that might exist in identifica­ In a biological control project, surveys of the area tion services, and some possible approaches to reduce where natural enemies are supposed to be released those problems. will indicate the native species present. A comparison o f the complex o f natural enemies in that area and in ROLE OF TAXONOMY IN BIOLOGICAL other areas where the pest also occurs but is not a CONTROL EFFORTS problem will help the biological control worker to select the natural enemies that show the most poten­ Any biological control project requires continuous tial for trial introductions. A maior contribution is 841 842 GILBERTO J. DE MoRAES provided at this point by the taxonomist through are reproductively isolated from other such groups identification of the candidate natural enemies. The (Mayr, 1969). This concept is not based on phenotype available literature on the identified species gives the and thus allows for considerable variation as long as biological control worker some indication of the the groups of organisms that are called species main­ natural enemies' expected behaviour based on histor­ tain their individualities as "reproductive units". ical evidence. about the particular family, genus or Taxonomists that advocate the biological concept of species. species may make use of morphological characters After introduction of natural enemies. Jt 1s Im­ to separate them, however, there is a fundamental portam to monitor their activity and establishment difference between using morphological characters to by periodic evaluations of the population dynamics infer reproductive affinities and basing the species of the particular pest and its introduced natural concept on morphology (Simpson, 1961). enemies. Here again the co-operation of taxonomists In many cases, morphological evidence alone is not in determining the different species is important. A sufficient to separate organisms imo species, because comparison of the pre- and post-release surveys of variations presented by conspecific individuais as should be encouraged since any change in the fauna well as similarities presented by sibling species. In may be indica tive o f the progress o f the programme. those cases, field ecological observations. laboratory But the work of taxonomists goes beyond naming crossings or other biological studies are necessary new species or identifying species already described. to indicate whether one is dealing with a single or It also considers the relationship between species, more than one species. For instance, studies of the seeking to arrange them in meaningful groups. This variation of morphological characters within and is important for biological control workers for severa! between species of predatory mites of the family reasons, especially in determining places of origin of Phytoseiidae have shown considerable variation pests. Furthermore, the work of taxonomists takes within one species according to geographical distribu­ into account the biological differences between popu­ tion. season and host plant (Chant et a! .. 1977; Croft, lations of a same species that indica te the occurrence 1970; Davis, 1970; Hoying and Croft. 1977; Muma of biotypes, which are populations of individuais of and Denmark. 1962), whereas great similarities have similar genetic composition for a biological attribute been found in closely related sibling species (Muma (Gonzalez cr a!., 1979). When studying the potential and Denmark. 1969). of a particular natural enemy, the adaptability of The simple rearing of organisms in the laboratory distinct biotypes to different ecological conditions. as for subsequent morphological studies often shows the identified in taxonomic comparisons o f population o f variations to be expected in a particular species. a same species from different areas. is also important Thus. the tools of taxonomists are not restricted to to biological comrol workers. microscopes, mounting material. cabinets for preserv­ Reference collections prepared by taxonomists ing specimens and the literature related to their are of major importance not only for ongoing, but specialty. but must also include collecting material also for future biological control projects. Those and laboratory facilities for biological studies. collections should include both native and imroduced For example. a species in need of detailed bio­ species. In the case of natural enemies. specimens systematic study at the presem time is the predaceous originally introduced and their laboratory and field phytoseiid mite. Typhlodromalus sp. near limonicus offspring (collected at different periods) should be (Garman & McGregor). This is one of the most preserved for studies of possible morphological alter­ common species on cassava in Colombia, and is ation in the new environment. Reference collections potentially importam as a predator of cassava green may provide hints to places of origin of different mites. Mononychellus ranajoa (Bondar) sensu latu, in organisms. A good example of this was reported by Africa. lt is morphologically similar to T. limonicus Pemberton, as mentioned by Clausen (1942). A single and T. rapax (DeLeon l (the former descrihed