Before we start. Field cage tests. Field cage tests

Transcription

1 Before we start Field cage assessment of fruit fly competitiveness and compatibility: the example of Anastrepha fraterculus M. Teresa Vera Cátedra de Terapéutica Vegetal, Facultad de Agronomía y Zootecnia, Universidad Nacional de Tucumán, Argentina. CONICET, Argentina. What do I wish that you retain from this presentation today? Field cage tests are the best compromise between laboratory conditions and costly and impractical field observations to assess (at least) tephritid fruit fly mating behaviour under seminatural conditions. There are almost 3 years of data obtained from such tests with biological and practical implications. Anastrepha fraterculus has something to tell. Field cage tests What are field cage tests? Screened cage set up over a plant that fills a large portion of the volume of the cage. Field cage tests Mating behaviour is observed, Release of sexually matured virgin flies 3 mt Two populations at a time 2.3 mt mating couples are collected and mating performance is estimated

2 Field cage tests Compatibility and Competitiveness Index of Sexual Isolation ISI = [(AA + BB) - (AB + BA)] / (AA + BB + AB + BA) Relative Performance Indices: MRPI and FRPI MRPI = [(AA + AB) - (BB+ BA)] / (AA + BB + AB + BA) Relative Sterility Index RSI = SW / (SW + WW) Compatibility and Competitiveness Almost 3 years of data ISI Negative assortative mating Random mating Sexual Isolation MRPI wild males Equal performance sterile males FRPI wild females Equal performance sterile females RSI wild males Equal competitiveness sterile males

3 with practical and biological implications Anastrepha fraterculus The South American fruit fly Infests major fruit crops and about 8 host plants Main control method: chemical control Economic impact Is the major species infesting apple in the southern states of Brazil with economic losses estimated in approximately U$S 11 millions. Present from Southern USA to Argentina In some countries it is sympatric only with one or few fruit flies species of economic importance Good for SIT!!! In Argentina it coexists with Ceratitis capitata mainly in the northeastern region causing losses of about U$S 37 millions. It is present as a major pest in other countries in South America such as Peru.

4 The taxonomic status Some studies on compatibility High levels of variability found at the morphological, cytological and genetic level. Cryptic species In order to apply SIT it is important to clarify its taxonomic status and determine the degree of mating compatibility among populations to carefully select which strain is to be transferred into mass rearing. In Argentina Mating compatibility Petit-Marty et al. (24a) Hybrid viability Petit-Marty et al. (24b) At the continental level Mating compatibility Between two isolated populations (Argentina and Peru) Hybrids compatibility and viability Cáceres et al. (29) Segura et al. (in press) Argentina Index of Sexual Isolation Populations obtained: Two different ecological regions: NOA - NEA Four populations One host: guava NW1 NE1 NW1 NE2 NW1 NW2 NW2 NE1 NW2 NE2 NW1 NE2 = -.1 ±.17 = -.3 ±. =.1 ±. = -.4 ±.17 = -.9 ±.9 = -.9 ±.13 Petit-Marty et al. (24) NW1: Horco Molle NW2: Yuto NE1: Concordia NE2: Posadas Random mating Isolation Petit-Marty et al. (24)

5 At the continental level Index of Sexual Isolation Perú Wild - Concordia Populations obtained: Tucumán Perú Lab Tucumán Perú Wild Ibague, Colombia Perú Wild Colombia La Molina + Piura, Perú Lab =.92 ±.3 =.83 ±.6 =.82 ±.3 =.78 ±.2 Perú Wild Piracicaba =. ±.6 Tucumán Piracicaba =.43 ±.8 La Molina, Perú Sil Tucumán Concordia Piracicaba, Brazil Perú Lab Perú Wild Tucumán, Argentina Concordia, Argentina =.12 ±.1 =.1 ± Latency Early morning maters Concordia = :33 ± :4 Tucuman = :46 ± :2 Piracicaba = 1:3 ± : Tapachula = 1:47 ± :6 Midday maters In general couples tended to form in the underside of the leaves Piracicaba, Brazil : :3:3 1: 1:3 2:32: 3: 3:3 4:33:3 : :3 6:3: 7: 7:3 8:36:3 9: 9:3 1:38: 11: : 1:2: 1:3 2:34: 3: 4:6: 4:3 :38: 6: 7:1: 7:3 :3 1:3 2:3 3:3 4:3 :3 6:3 7:3 8:3 9:3 1:3 11:3 12:3 Perú Wild = 4:3 ± :7 Perú Lab = 3: ± :1 Temporal isolation. Location of mating couples Isolation Random mating Late afternoon maters Colombia = 1:18 ± :14 Different mating arenas Ecological isolation Peru Tucuman Pir x Pir tree net Tapachula Other x Other tree net 1.

6 Hybrids compatibility Hybrid female choice Arg Peru (Arg) Arg Peru (Peru) =.73 ±. =.86 ±.4 # matings 1 # matings 1 Arg (Arg) H PA Arg (Arg) Peru (Peru) =.3 ±.12 =. ±.11 =.1 ±.1 Type of male ARG Type of male PERU H PA Peru (Peru) =.13 ±.9 Random mating Isolation # matings 1 # matings 1 : Hybrid from Argentina male x Peru female H PA Type of male ARG Type of male PERU H PA : Hybrid from Peru male x Argentina female Cáceres et al. (29) Segura et al. (in press) Competitiveness Competitiveness Strain replacement Irradiation doses.8 6. Gy 4 Gy 7 Gy 1 Gy =.4 =.48 =.44 =. Equal competitiveness RSI % Egg hatch Allinghi et al. (27) 1:1 1:1 Hybrids Refreshed

7 Male enhancers Hormonal treatments In summary What did I mean to transmit? Field cage tests have been used for several years to assess tephritid fruit fly mating behaviour under semi-natural conditions. We have reviewed some studies on Anastrepha fraterculus that dealt with mating compatibility and male performance with biological and practical implications. Segura et al. (29) In summary Credits Field cage tests can be used to select which strain/population should be transferred to mass rearing, to evaluate sterile s male quality and the impact of sexual enhancers and nutritional status on male sexual performance. Field cages are the best compromise between laboratory conditions and costly and impractical field observations and they provide sound data INTA Castelar: Jorge Cladera and Diego Segura Buenos Aires University: Juan Vilardi, Paula Gomez-Cendra and María Eugenia Utges CNEA: Verónica Yusef Armando Allinghi and Natalia Petit-Marty CONICET: Solana Abraham IAEA

8 Thank you for your attention