Table 2.

Molecular basis of social immunity against fungal pathogens in social insects.

Regulator	Function	Origin	Molecule	Species and Reference
Chemosensory regulation	Detecting pathogens, chemical communication and inducing behavioral and physiological defenses	Fungal pathogens	Odor substances	Termites: Macrotermes Michaelseni [27] Coptotermes formosanus [50] Reticulitermes flavipes [48]
		Host	Chemical ‘sickness cues’	Ants: Lasius neglectus [55]
			Linoleic and oleic acids	Ants: Solenopsis invicta [53]
			Phenethyl acetate	Bees: Apis mellifera [54]
			OR and Orco genes	Ants: Ooceraea biroi [95] Harpegnathos saltator [107] Bees: Apis mellifera [108]
			IR genes	Termites: Zootermopsis nevadensis [109]
Physiological regulation	External defense by sharing insect venoms with their nestmates and nest materials	Frontal gland	α-pinene and limonene	Termites: Nasutitermes costalis and N. nigriceps [42]
			(-)-β-elemene	Termites: Reticulitermes speratus [43]
		Oral secretions	Proteins and chemicals	Termites: Mastotermes darwiniensis [75]
		Fecal material	Unknown	Termites: Zootermopsis angusticollis [35]
		Salivary gland	Termicins and GNBPs	Termites: Reticulitermes flavipes [17] Nasutitermes corniger [36]
		Venom gland	Formic acid	Ants: Lasius neglectus [44]
			Melittin	Bees: Apis mellifera [38]
		Metapleural gland	Unknown	Ants: Lasius neglectus [14] Acromyrmex subterraneus [37]
		Hypopharyngeal gland	Royal jelly	Apis mellifera [56,57]
	Internal defense by enhancing physiological resistance and tolerance to fungal infections	Immune signal and immune effector	Toll pathway	Model insect: Drosophila [110,111]
			Termites: transglutaminase and histone Ants: β-1,3-glucan-binding protein and defensin Bees: tyrosine kinase 3, MyD88 and abaecin	Termites: Reticulitermes flavipes [17] Reticulitermes chinensis [62] Ants: Lasius neglectus [14] Acromyrmex echinatior [112] Bees: Apis mellifera [38,99]
		Detoxication	Glutathione S-transferase and cytochrome P450	Termites: Reticulitermes chinensis [62]
		Antioxidation	Termites: superoxide dismutase and catalase Bees: hexamerin 70b and vitellogenin	Termites: Reticulitermes chinensis [62] Bees: Apis mellifera [99]
		Energy metabolism, biosynthesis, development and others	Others	Termites: Reticulitermes chinensis [62] Ants: Acromyrmex echinatior [112] Bees: Apis mellifera [99]
Other	Nest materials	Conifer (Picea abies)	Resin	Ants: Formica paralugubris [34]
		Streptomyces	Unknown	Termites: Coptotermes formosanus [39]
		Streptomyces	Candicidin and antimycins	Ants: Acromyrmex octospinosus [40]