Characterization of Cold and Heat Tolerance of Bactrocera tau (Walker)

Abstract

Bactrocera tau (Walker) (Diptera: Tephritidae) is a serious, economically important invasive pest that has spread and been established in many regions worldwide. Temperature is a crucial abiotic factor governing insect activity, fitness, and geographical distribution. Yet, surprisingly, the tolerance of B. tau to extreme cold and heat stress remains unclear. Here, we measured the supercooling point (SCP) of different life stages of B. tau. Further, several life stages of B. tau (egg, 1st, 2nd, and 3rd instar larvae, 1-day-old pupae, and 3-day-old adult) were subjected to six low temperatures (−9, −7, −5, −3, −1, and 0 °C) and six high temperatures (39, 40, 41, 42, 43, and 44 °C) for various durations (0.5, 1.0, 2.0, and 4.0 h), and three-way survival–time–temperature relationships were investigated. We found that the SCPs differed significantly among different life stages of B. tau, being the lowest for SCP of eggs, at −25.82 ± 0.51 °C. There was no significant effect of sex on the mean SCPs of B. tau adults, except for 45- to 50-day-old flies. In addition, an interaction effect was uncovered between tested temperatures and exposure duration upon B. tau mortality at different life stages. Eggs exhibited the strongest cold tolerance, yet the weakest heat tolerance. The 3rd instar larvae were the most heat- and cold tolerant among larval stages, followed by the 2nd and 1st instar larvae. The upper limit of the chill injury zone (ULCIZ) for 3-day-old adult and 1-day-old pupae was −2.51 °C and −2.50 °C, respectively, while their corresponding lower limit of thermal injury zone (LLTIZ) was 39.39 °C and 38.29 °C. This paper presents valuable data to provide an integrated knowledge for understanding the cold and heat tolerance potential of B. tau and ensure the proper implementation of post-harvest phytosanitary protocols for this pest’s disinfestation.

Chromosome-level genome assembly of an agricultural pest Zeugodacus tau (Diptera: Tephritidae)

“…Currently, Z. tau is distributed in most regions of southern China. It is generally present in tropical and subtropical Asia, sub-equatorial Africa, Australia, the Solomon Islands, and the South Pacific region 3 , 6 . Field monitoring has shown that Z. tau continues to expand to the high-latitude areas.…”

Differential Cold Tolerance on Immature Stages of Geographically Divergent Ceratitis capitata Populations

“…Thermal biology of the adults of some tephritids including Bactrocera dorsalis (Hendel) [1,55], Bactrocera zonata (Saunders) [56], Bactrocera tryoni (Froggatt) [57,58], Bactrocera oleae (Rossi) [59], Bactrocera tau (Walker) [60], Ceratitis cosyra (Walker) [61], Ceratitis rosa (Karsch) [62], Ceratitis quilicii (De Meyer, Mwatawala and Virgilio) [63], Eurosta solidaginis (Fitch) [64][65][66][67], Rhagoletis cerasi (Linnaeus) [68] and Rhagoletis indifferens (Curran) [69] has already been investigated. Regarding medfly, its broader distribution may justify its great cold tolerance, which might determine the establishment of populations and their invasion success [13,70,71].…”

Evaluation of the Attractant Effect of Solanum muricatum (Solanales: Solanaceae) on Gravid Female Adults of Zeugodacus tau (Diptera: Tephritidae) and Screening of Attractant Volatiles

“…Zeugodacus tau (Walker) (Diptera: Tephritidae), formerly known as Bactrocera tau, is a polyphagous pest of fresh fruits and vegetables and has been listed as a quarantine pest in many countries, including Japan, the Republic of Korea, Indonesia, Pakistan, and Jordan [1,2]. Zeugodacus tau was first recorded in China in Fujian province in 1849 by Walker [1,2]; now, it is an economically important agricultural pest and mainly infests fruits of Cucurbitaceae, Moraceae, Myrtaceae, Sapotaceae, and Solanaceae in tropical and sub-tropical Asia and the South Pacific region [3][4][5]. The female adults of Z. tau achieve explosive population growth by laying a large number of eggs; they can lay roughly 9.9 eggs at once, on average, and 464 eggs over a lifetime [6].…”

“…Zeugodacus tau has caused 21-34% and 21-32% infestations of Siraitia grosvenorii (Cucurbitales: Cucurbitaceae) and Cucurbita moschata (Cucurbitales: Cucurbitaceae), respectively, in Taiwan and China [8], and approximately 5.6% yield losses of ripened Luffa acutangula (Cucurbitales: Cucurbitaceae) in Thailand have been caused by Z. tau [9]. High survival rates for Z. tau at four different life stages from egg to adult, were shown to be maintained under extreme cold and heat, with temperatures spanning −5 to 0 • C and 39 to 42 • C, respectively [2,7]. With the warming of the climate [10], the areas suitable for Z. tau establishment are gradually increasing, increasing the risk of its invasion and spread.…”