TABLE 1.

Mechanisms of dsRNA cellular uptake identified in different insect species.

Order	Species	Environmental RNAi	Sid-1	Endocytosis	References
Diptera	Drosophila melanogaster	+	No	Yes	Saleh et al., 2006
	Bactrocera dorsalis	+	No	Yes	Li X. X. et al., 2015
Coleoptera	Tribolium castaneum	+	No	Yes	Tomoyasu et al., 2008; Xiao et al., 2015
	Diabrotica virgifera virgifera	+ +	Yes	Yes	Miyata et al., 2014; Pinheiro et al., 2018
	Leptinotarsa decemlineata	+ +	Yes	Yes	Cappelle et al., 2016
Lepidoptera	Spodoptera frugiperda	+ but no endosomal release	Not determined	Yes	Yoon et al., 2017
	Bombyx mori	–	No	Not determined	Tomoyasu et al., 2008
Orthoptera	Schistocerca gregaria	–	No	Yes	Wynant et al., 2014
	Locusta migratoria	–	No	Not determined	Luo et al., 2012
Hymenoptera	Apis mellifera	+	Yes	Not determined	Aronstein et al., 2006
Hemiptera	Nilaparvata lugens	–	Yes	Not determined	Xu et al., 2013

Adapted from Cappelle et al. (2016). RNAi: ++, present and robust; +, present but not robust; –, not present.