Effects of Temperature and Tissue Type on the Development of Megaselia scalaris (Loew) (Diptera: Phoridae)
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The scuttle fly, Megaselia scalaris (Loew), is a Dipteran from the Phoridae family of medical, veterinary, and forensic importance. In the case of the latter, M. scalaris is commonly associated with indoor death scenes and its larvae are useful in determining time of colonization (TOC). This is the first developmental study on the effects of different temperatures and tissues from two different vertebrate species on the growth rate and larval length of M. scalaris, and consequently, on estimated TOC. A validation study of these data was also conducted. Immature M. scalaris were reared on either bovine or porcine biceps femoris at 24°C, 28°C, and 32°C. Temperature significantly impacted immature development including egg hatch, development from hatch to pupa, and from pupa to adult. From egg to hatch, development had a growth rate difference of 32.1% from 24°C to 28°C, 13.9% from 28°C to 32°C, and 45.5% from 24°C to 32°C. Development of larva to pupation displayed similar results with differences of 30.3% between 24°C and 28°C, 15.4% between 28°C and 32°C, and 45.2% between 24°C and 32°C. Development from pupation to adult emergence, likewise, displayed a 44.4% difference from 24°C and 28°C, 7.3% from 28°C to 32°C, and 51.2% from 24°C to 32°C. From oviposition to adult emergence, M. scalaris needed approximately 32.7% more hours to complete development when reared at 24°C than 28°C, 8.5% when reared on 28°C rather than 32°C, and 38.4% more time when reared on 24°C over 32°C. Tissue type did not significantly impact development. A preliminary validation study was conducted within four different indoor environments (two different attics, a closet, and a shower) spanning two different buildings. Utilizing minimum and maximum lengths, time of colonization estimates were underestimated in all instances. In all cases, the range generated encompassed the actual time of colonization. On average, time of colonization estimates when using minimum length were underestimated by 26%, but overestimated by only 1.4% when using maximum development range. Data gathered from this research could be useful when estimating a time of colonization of decomposing vertebrate remains. Future research will need to examine development for each instar in order to increase precision of such estimates.
Thomas, Joshua (2015). Effects of Temperature and Tissue Type on the Development of Megaselia scalaris (Loew) (Diptera: Phoridae). Master's thesis, Texas A & M University. Available electronically from