A chink in the armour: an investigation of thrips soldier morphology and sex in relation to fighting ability

Explaining the persistence of self-sacrificing individuals throughout evolutionary time has been a central area of study for evolutionary biologists since Darwin. In total, seven species of Australian gall inducing thrips have evolved soldiers with enlarged femurs that are used to defend against invertebrate invaders. In the species Kladothrips intermedius, the sexes of soldiers differ morphologically - the females have more robust femurs than the male soldiers, which have longer wings, suggesting less commitment to this defensive role. There was no difference in the fighting abilities of the male and female soldiers in K intermedius. Morphology of the soldier, within a sex, was related to the outcome of a battle with an invader, but not in the way expected. Females with slimmer femurs were more likely to battle an invader. Also, female soldiers with shorter wings were better able to dispatch an invader while male soldiers with longer wings were less likely to battle an invader

Antifungal activity in thrips soldiers suggests a dual role for this caste

The social insect soldier is perhaps the most widely known caste, because it often exhibits spectacular weapons, such as highly enlarged jaws or reinforced appendages, which are used to defend the colony against enemies ranging in size from wasps to anteaters. We examined the function of the enlarged forelimbs of soldiers (both male and female) of the eusocial, gall-inhabiting insect Kladothrips intermedius, and discovered that they have little impact on their ability to repel the specialized invading thrips Koptothrips species. While the efficacy of the enlarged forelimb appears equivocal, we show that soldiers secrete strong antifungal compounds capable of controlling the specialized insect fungal pathogen, Cordyceps bassiana. Our data suggest that these thrips soldiers have evolved in response to selection by both macro-and micro-organisms. While it is unknown whether specialized fungal pathogens have been major selective agents in the evolution of the soldier caste in general, they were probably present when sociality first evolved and may have been the primordial enemies of social insects.4 page(s

Multimetallic complexes and functionalized gold nanoparticles based on a combination of d- and f-elements

The new DO3A-derived dithiocarbamate ligand, DO3A-tBu-CS2K, is formed by treatment of the ammonium salt [DO3A-tBu]HBr with K2CO3 and carbon disulfide. DO3A-tBu-CS2K reacts with the ruthenium complexes cis-[RuCl2(dppm)2] and [Ru(CH═CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole) to yield [Ru(S2C-DO3A-tBu)(dppm)2]+ and [Ru(CH═CHC6H4Me-4)(S2C-DO3A-tBu)(CO)(PPh3)2], respectively. Similarly, the group 10 metal complexes [Pd(C,N-C6H4CH2NMe2)Cl]2 and [PtCl2(PPh3)2] form the dithiocarbamate compounds, [Pd(C,N-C6H4CH2NMe2)(S2C-DO3A-tBu)] and [Pt(S2C-DO3A-tBu)(PPh3)2]+, under the same conditions. The linear gold complexes [Au(S2C-DO3A-tBu)(PR3)] are formed by reaction of [AuCl(PR3)] (R = Ph, Cy) with DO3A-tBu-CS2K. However, on reaction with [AuCl(tht)] (tht = tetrahydrothiophene), the homoleptic digold complex [Au(S2C-DO3A-tBu)]2 is formed. Further homoleptic examples, [M(S2C-DO3A-tBu)2] (M = Ni, Cu) and [Co(S2C-DO3A-tBu)3], are formed from treatment of NiCl2·6H2O, Cu(OAc)2, or Co(OAc)2, respectively, with DO3A-tBu-CS2K. The molecular structure of [Ni(S2C-DO3A-tBu)2] was determined crystallographically. The tert-butyl ester protecting groups of [M(S2C-DO3A-tBu)2] (M = Ni, Cu) and [Co(S2C-DO3A-tBu)3] are cleaved by trifluoroacetic acid to afford the carboxylic acid products, [M(S2C-DO3A)2] (M = Ni, Cu) and [Co(S2C-DO3A)3]. Complexation with Gd(III) salts yields trimetallic [M(S2C-DO3A-Gd)2] (M = Ni, Cu) and tetrametallic [Co(S2C-DO3A-Gd)3], with r1 values of 11.5 (Co) and 11.0 (Cu) mM–1 s–1 per Gd center. DO3A-tBu-CS2K can also be used to prepare gold nanoparticles, Au@S2C-DO3A-tBu, by displacement of the surface units from citrate-stabilized nanoparticles. This material can be transformed into the carboxylic acid derivative Au@S2C-DO3A by treatment with trifluoroacetic acid. Complexation with Gd(OTf)3 or GdCl3 affords Au@S2C-DO3A-Gd with an r1 value of 4.7 mM–1 s–1 per chelate and 1500 mM–1 s–1 per object