first larval instar (24-49hrs AF) second instar (49-72hrs AF) early third instar (72-150hrs AF) hours after fertilization
||Fruit fly Drosophila melanogaster
||Matamoro-Vidal A, Salazar-Ciudad I, Houle D. Making quantitative morphological variation from basic developmental processes: Where are we? The case of the Drosophila wing. Dev Dyn. 2015 Jan 23. doi: 10.1002/dvdy.24255. p. 1060 right column 3rd paragraphPubMed ID25619644
||Madhavan M, Schneiderman H. 1977. Histological analysis of the dynamics of growth of imaginal discs and histoblast nests during the larval development of Drosophila melanogaster. Wilhelm Roux’s Arch 183 :269–305. link & Garcia-Bellido A, Merriam JR. 1971. Parameters of the Wing Imaginal Disc Development of Drosophila melanogaster. Dev Biol 24: 61–87. PubMed ID5001010
||p. 1060 right column 3rd paragraph:"In the first larval instar (24 to 49 hr after fertilization [AF]), the wing disc grows moderately and without cell division (primary source Madhavan & Schneiderman). Growth becomes exponential during the second (49–72 hr AF) and early third instar (72–150 hr AF), then achieving ∼10–11 rounds of cell divisions, each of which takes ∼8.5 hr at 25 °C (primary source Garcia-Bellido & Merriam, 1971)." Duration of each stage: 1st larval instar ~25 hrs (moderate, no division), 2nd instar ~ 23 hrs (exponential), early 3rd instar ~78 hrs (exponential).