Absence of coupling between release and biosynthesis of peptide hormones in insect neuroendocrine cells

Adipokinetic hormone (AKH)-producing cells in the corpus cardiacum of the insect Locusta migratoria represent a neuroendocrine system containing large quantities of stored secretory peptides. In the present study we address the question whether the release of AKHs from these cells induces a concomitant enhancement of their biosynthesis. The effects of hormone release in vivo (by flight activity) and in vitro (using crustacean cardioactive peptide, locustamyoinhibiting peptide, and activation of protein kinase A and C) on the biosynthetic activity for AKHs were measured. The intracellular levels of prepro-AKH mRNAs, the intracellular levels of pro-AKHs, and the rate of synthesis of (pro-)AKHs were used as parameters for biosynthetic activity. The effectiveness of in vitro treatment was assessed from the amounts of AKHs released. Neither flight activity as the natural stimulus for AKH release, nor in vitro treatment with the regulatory peptides or signal transduction activators appeared to affect the biosynthetic activity for AKHs. This points to an absence of coupling between release and biosynthesis of AKHs. The strategy of the AKH-producing cells to cope with variations in secretory stimulation seems to rely on a pool of secretory material that is readily releasable and continuously replenished by a process of steady biosynthesis.     

Insect adipokinetic hormones: release and integration of flight energy metabolism

Insect flight involves mobilization, transport and utilization of endogenous energy reserves at extremely high rates. Peptide adipokinetic hormones (AKHs), synthesized and stored in neuroendocrine cells, integrate flight energy metabolism. The complex multifactorial control mechanism for AKH release in the locust includes both stimulatory and inhibitory factors. The AKHs are synthesized continuously, resulting in an accumulation of AKH-containing secretory granules. Additionally, secretory material is stored in large intracisternal granules. Although only a limited part of these large reserves appears to be readily releasable, this strategy allows the adipokinetic cells to comply with large variations in secretory demands; changes in secretory activity do not affect the rate of hormone biosynthesis. AKH-induced lipid release from fat body target cells has revealed a novel concept for lipid transport during exercise. Similar to sustained locomotion of mammals, insect flight activity is powered by oxidation of free fatty acids derived from endogenous reserves of triacylglycerol. However, the transport form of the lipid in the circulatory system is diacylglycerol (DAG) that is delivered to the flight muscles associated with lipoproteins. While DAG is loaded onto the multifunctional insect lipoprotein, high-density lipophorin (HDLp) and multiple copies of the exchangeable apolipoprotein III (apoLp-III) associate reversibly with the expanding particle. The resulting low-density lipophorin (LDLp) specifically shuttles DAG to the working muscles. Following DAG hydrolysis by a lipophorin lipase, apoLp-III dissociates from the particle, regenerating HDLp that is re-utilized for lipid uptake at the fat body cells, thus functioning as an efficient lipid shuttle mechanism. Many structural elements of the lipoprotein system of insects appear to be similar to their counterparts in mammals; however, the functioning of the insect lipoprotein in energy transport during flight activity is intriguingly different.     

Locust corpora cardiaca contain an inactive adipokinetic hormone

A neuropeptide from the migratory locust, Locusta migratoria, has been identified as a novel member of the family of adipokinetic hormones (AKHs). The peptide is probably synthesised in the brain because it is the first AKH found in the storage lobe, whilst the three 'classic' Locusta AKHs are present in the glandular lobe of the corpora cardiaca. In locusts, the peptide has no biological activity usually associated with AKHs. There is only 36-56% sequence identity with the three Lom-AKHs, but 78% identity with the Drosophila melanogaster AKH, Drm-HrTH. The new peptide is active in the American cockroach, Periplaneta americana, and was provisionally named 'L. migratoria hypertrehalosaemic hormone', Lom-HrTH; its biological role in locusts remains to be established. The high degree of identity with Drm-HrTH suggests that Lom-HrTH is an ancient molecule.     

The adipokinetic hormones of Heteroptera: a comparative study

The adipokinetic hormones (AKHs) from 15 species of heteropteran Hemiptera (encompassing eight families, six superfamilies and three infraorders) have been isolated and structurally identified using liquid chromatography coupled with mass spectrometry. None of the structures are novel and all are octapeptides. These peptide sequence data are used, together with the previously available AKH sequence data on Heteroptera, to create a larger dataset for comparative analyses. This results, in total, in AKH sequences from 30 species (spanning 13 families), which are used in a matrix confronted with the current hypotheses on the phylogeny of Heteroptera. The expanded dataset shows that all heteropterans have octapeptide AKHs; three species have two AKHs, whereas the overwhelming majority have only one AKH. From a total of 11 different AKH peptides known from Heteroptera to date, three AKHs occur frequently: Panbo‐red pigment‐concentrating hormone (RPCH) (×10), Schgr‐AKH‐II (×6) and Anaim‐AKH (×4). The heteropteran database also suggests that particular AKH variants are family‐specific. The AKHs of Heteroptera: Pentatomomorpha (all terrestrial) are not present in Nepomorpha (aquatic) and Gerromorpha: Gerridae (semiaquatic); AKHs with a Val in position 2 are absent in the Pentatomomorpha (only AKHs with Leu² are present), whereas Val² predominates in the nonterrestrial species. An unexpected diversity of AKH sequences is found in Nepomorpha, Nepoidea, Nepidae and Nepinae, whereas Panbo‐RPCH (which has been identified in all infraorders of decapod crustaceans) is present in all analysed species of Pentatomidae and also in the only species of Tessaratomidae investigated. The molecular evolution of Heteroptera with respect to other insect groups and to crustaceans is discussed     

Structural diversity of adipokinetic hormones in the hyperdiverse coleopteran Cucujiformia

Seventeen species of the coleopteran series Cucujiformia are investigated for the presence and sequence of putative adipokinetic hormones (AKHs). Cucujiformia includes species from the major superfamilies, that is, Chrysomeloidea, Curculionoidea, Cucujoidea, and Tenebrionoidea. The clade Phytophaga in which the Chrysomeloidea and Curculionoidea reside, harbor very detrimental species for agriculture and forestry. Thus, this study aims not only to demonstrate the structural biodiversity of AKHs in these beetle species and possible evolutionary trends but also to determine whether the AKHs from harmful pest species can be used as lead substances for a future putative insecticide that is harmless to beneficial insects. Sequence analysis of AKHs is achieved by liquid chromatography coupled to mass spectrometry. Most of the investigated species contain AKH octapeptides in their corpora cardiaca, although previously published work also found a few decapeptides, which we comment on. The signature and sole AKH in cerambycidae Chrysomeloidea and Curculionoidea is Peram‐CAH‐I (pEVNFSPNW amide), which is also found in the majority of chrysomelidae Chrysomeloidea and in the one investigated species of Cucujoidea albeit in a few cases associated with a second AKH which can be either Peram‐CAH‐II (pELTFTPNW amide), Emppe‐AKH (pEVNFTPNW amide), or Micvi‐CC (pEINFTPNW amide). The most often encountered AKH in Tenebrionoidea, family Meloidae as well as family Tenebrionidae, is Tenmo‐HrTH (pELNFSPNW amide) followed by Pyrap‐AKH (pELNFTPNW amide) and a Tenmo‐HrTH extended decapeptide (in Meloidae). Finally, we examine AKH sequences from 43 species of cucujiform beetles, including the superfamily Coccinelloidea for a possible lead compound for producing a cucujiform‐specific pesticide.     

Co-localization of the adipokinetic hormones I and II in the same glandular cells and in the same secretory granules of corpus cardiacum of Locusta migratoria and Schistocerca gregaria

Summary The immunocytochemical reactivity of the glandular cells of the corpus cardiacum (CCG-cells) of Locusta migratoria and Schistocerca gregaria was investigated at the electron-microscopic level, using the protein A-gold method, with three antisera against fragments of the adipokinetic hormones AKH I and AKH II. This combination of antisera permitted discrimination between anti-AKH I and anti-AKH II immunoreactivity. Fixation in a mixture of 2% glutaraldehyde and 2% formaldehyde, in combination with low-temperature embedding in Lowicryl K₄M, produced the highest and most consistent selective immunogold labelling of the secretory and ergastoplasmic granules. All secretory granules in all CCG-cells investigated possessed a distinct anti-AKH I-immunopositive reaction, whereas most secretory granules showed a weaker anti-AKH II immunoreaction. Ergastoplasmic granules reacted similar to the secretory granules. The average immunolabelling of the secretory granules was higher in the processes than in the cell bodies of the CCG-cells. The results in Schistocerca gregaria were essentially similar to those in Locusta migratoria. It is concluded that (i) the individual CCG-cells synthesize AKH I as well as AKH II; (ii) these hormones coexist in the same ergastoplasmic and secretory granules; and (iii) these granules contain a higher content of AKH I than AKH II.     

The adipokinetic hormone of the coleopteran suborder Adephaga: Structure,function, and comparison of distribution in other insects

The aim of the current study is to identify the adipokinetic hormone(s) (AKHs) of a basal suborder of the species‐rich Coleoptera, the Adephaga, and possibly learn more about the ancestral AKH of beetles. Moreover, we wanted to compare the ancestral AKH with AKHs of more advanced beetles, of which a number are pest insects. This would allow us to assess whether AKH mimetics would be suitable as insecticides, that is, be harmful to the pest species but not to the beneficial species. Nine species of the Adephaga were investigated and all synthesize only one octapeptide in the corpus cardiacum, as revealed by Edman degradation sequencing techniques or by mass spectrometry. The amino acid sequence pGlu‐Leu‐Asn‐Phe‐Ser‐Thr‐Gly‐Trp corresponds to Schgr‐AKH‐II that was first identified in the desert locust. It is assumed that Schgr‐AKH‐II—the peptide of a basal beetle clade—is the ancestral AKH for beetles. Some other beetle families, as well as some Hymenoptera (including honey bees) also contain this peptide, whereas most of the pest beetle species have different AKHs. This argues that those peptides and their receptors should be explored for developing mimetics with insecticidal properties. A scenario where Schgr‐AKH‐II (the only AKH of Adephaga) is used as basic molecular structure to derive almost all other known beetle AKHs via single step mutations is very likely, and supports the interpretation that Schgr‐AKH‐II is the ancestral AKH of Coleoptera.     

Effect of natural toxins and adipokinetic hormones on the activity of digestive enzymes in the midgut of the cockroach Periplaneta americana

This study examined the effect of two natural toxins (a venom from the parasitic wasp Habrobracon hebetor and destruxin A from the entomopathogenic fungus Metarhizium anisopliae), and one pathogen (the entomopathogenic fungus Isaria fumosorosea) on the activity of basic digestive enzymes in the midgut of the cockroach Periplaneta americana. Simultaneously, the role of adipokinetic hormones (AKH) in the digestive processes was evaluated. The results showed that all tested toxins/pathogens elicited stress responses when applied into the cockroach body, as documented by an increase of AKH level in the central nervous system. The venom from H. hebetor showed no effect on digestive enzyme activities in the ceca and midgut in vitro. In addition, infection by I. fumosorosea caused a decrease in activity of all enzymes in the midgut and a variable decrease in activity in the ceca; application of AKHs did not reverse the inhibition. Destruxin A inhibited the activity of all enzymes in the midgut but none in the ceca in vitro; application of AKHs did reverse this inhibition, and no differences between both cockroach AKHs were found. Overall, the results demonstrated the variable effect of the tested toxins/pathogens on the digestive processes of cockroaches as well as the variable ability of AKH to counteract these effects.     

Protein traffic from the secretory pathway to the endosomal system in pancreatic beta-cells

Constitutive-like secretion involves vesicular trafficking corresponding kinetically and biochemically with a post-trans-Golgi network (TGN) origin. In pancreatic beta-cells, the budding of AP-1/clathrin-coated vesicles, a portion of which is derived from immature secretory granules, has been hypothesized to initiate constitutive-like trafficking. However, approximately 30 min after release of a 20 degrees C intracellular transport block in pancreatic beta-cells (to synchronize protein egress from the TGN), addition of brefeldin A (BFA) (which inhibits AP-1 recruitment) was reported not to block subsequent constitutive-like secretion. To further explore post-TGN trafficking in pancreatic beta-cell lines, we have followed the fate of pulse-labeled procathepsin B (ProB, a lysosomal proenyzme) after postpulse wortmannin treatment or the BFA treatment described above. We find that continuous wortmannin treatment allows ProB to reach immature secretory granules but inhibits its egress from maturing granules. Remarkably, BFA treatment causes augmented unstimulated secretion of newly synthesized ProB that is not paralleled by insulin. This effect requires a delay of 25-35 min after release from the 20 degrees C block. Further, when ProB delivery to endosomes is inhibited, its BFA-augmented secretion is eliminated. We hypothesize that the constitutive-like pathway involves an endosomal intermediate.     

Biosynthesis and secretion of pituitary hormones: dynamics and regulation

Production and secretion of hormones by the pituitary involve highly orchestrated intracellular transport and sorting steps. Hormone precursors are routed through a series of compartments before being packaged in secretory granules. These highly dynamic carriers play crucial roles in both prohormone processing and peptide exocytosis. We have employed the ACTH-secreting AtT-20 cell line to study the membrane sorting events that confer functionality (prohormone activation and regulated exocytosis) to these secretory carriers. The unique ability of granules to promote prohormone processing is attributed to their acidic interior. Using a novel avidin-targeted fluorescence ratio imaging technique, we have found that the trans-Golgi of live AtT-20 cells maintains a mildly acidic (approximately pH 6.2) interior. Budding of secretory granules causes the lumen to acidify to 相似文献   

Is the titer of adipokinetic peptides in Leptinotarsa decemlineata fed on genetically modified potatoes increased by oxidative stress?

The level of adipokinetic hormones (AKHs) (Peram-CAH-I and II) in the corpora cardiaca and the hemolymph of Leptinotarsa decemlineata enormously increases in the adults fed on genetically modified potatoes containing either GNA lectin or Cry 3Aa toxin concomitant with increased oxidative stress in gut tissues. A similar enhancement of the AKH titer is achieved when the adults are injected with paraquat that evokes oxidative stress. On the other hand, an injection of exogenous AKH reduces oxidative stress biomarkers in the hemolymph by reducing protein carbonyls and enhancing reduced glutathione levels. These facts indicate that there is a feedback regulation between an oxidative stressor action and the level of AKH in the insect body, and that AKHs might be involved in the activation of an antioxidant protection mechanism. These results are to our knowledge, the first evidence for the involvement of AKHs in oxidative stress mitigation, in addition to a plethora of other roles.     

The adipokinetic hormone family in Chrysomeloidea: structural and functional considerations

The presented work is a hybrid of an overview and an original research paper on peptides belonging to the adipokinetic hormone (AKH) family that are present in the corpora cardiaca of Chrysomeloidea. First, we introduce the AKH/red pigment-concentrating hormone (RPCH) peptide family. Second, we collate the available primary sequence data on AKH peptides in Cerambycidae and Chrysomelidae, and we present new sequencing data (from previously unstudied species) obtained by liquid-chromatography coupled with ion trap electrospray ionisation mass spectrometry. Our expanded data set encompasses the primary structure of AKHs from seven species of Cerambycidae and three species of Chrysomelidae. All of these species synthesise the octapeptide code-named Peram-CAH-I (pGlu-Val-Asn-Phe-Ser-Pro-Asn-Trp amide). Whereas this is the sole AKH peptide in Cerambycidae, Chrysomelidae demonstrate a probable event of AKH gene duplication, thereby giving rise to an additional AKH. This second AKH peptide may be either Emppe-AKH (pGlu-Val-Asn-Phe-Thr-Pro-Asn-Trp amide) or Peram-CAH-II (pGlu-Leu-Thr-Phe-Thr-Pro-Asn-Trp amide). The peptide distribution and structural data suggest that both families are closely related and that Peram-CAH-I is the ancestral peptide. We hypothesise on the molecular evolution of Emppe-AKH and Peram-CAH-II from the ancestral peptide due to nonsynonymous missense single nucleotide polymorphism in the nucleotide coding sequence of prepro-AKH. Finally, we review the biological significance of the AKH peptides as hyperprolinaemic hormones in Chrysomeloidea, i.e. they cause an increase in the circulating concentration of proline. The mobilisation of proline has been demonstrated during flight in both cerambycid and chrysomelid beetles.     

Imaging secretory vesicles by fluorescent protein insertion in propeptide rather than mature secreted peptide

We combined confocal and live-cell imaging with a novel molecular strategy aimed at revealing mechanisms underlying glucose-regulated insulin vesicle secretion. The 'Ins-C-GFP' reporter monitors secretory peptide targeting, trafficking, and exocytosis without directly tagging the mature secreted peptide. We trapped a green fluorescent protein (GFP) reporter in equimolar quantity within the secretory vesicle by fusing it within the C peptide of proinsulin which only after nascent vesicle sealing and acidification is cleaved from the mature secreted A and B chains of insulin. Ins-C-GFP expression in mouse islets without fail exhibited punctate distribution of green fluorescence by confocal microscopy. Ins-C-GFP colocalized GFP with insulin at vesicle dense cores by immuno-electron microscopy. Glucose stimulation decreased vesicle fluorescence coordinately with enhanced secretion from islets of C-GFP detected by anti-GFP Western blots, and of insulin detected by anti-insulin radioimmunoassay. An insulin secretagogue with a red fluorescent label, glibenclamide BODIPY^®TR, was applied to islets expressing Ins-C-GFP. The stimulus response was imaged as a rise in red secretagogue leading to marked loss in green granules. Since neuropeptides as well as peptide hormones are processed from propeptides after sealing of secretory granules, vesicle trapping likely is widely applicable for studies on targeting, trafficking, and regulated release of secretory peptides.     

Proctolin: A possible releasing factor in the corpus cardiacum/corpus allatum of the locust

The corpus cardiacum (CC) and corpus allatum (CA) of the locust, Locusta migratoria, contain intense proctolin-like immunoreactivity (PLI) within processes and varicosities. In contrast, in the cockroach, Diploptera punctata, although a similar staining pattern occurs within the CC, PLI appears absent within the CA. The possible role of proctolin as a releasing factor for adipokinetic hormone (AKH) and juvenile hormone (JH) was investigated in the locust. Proctolin caused a dose-dependent increase in AKH I release (determined by RP-HPLC) from the locust CC over a range of doses with threshold above 10(-8)M and maximal release at about 10(-7)M proctolin. Isolated glandular lobes of the CC released greater amounts of AKH I following treatment with proctolin and in these studies AKH II was also released. Confirmation of AKH I release was obtained by injecting perfusate from incubated CCs into locusts and measuring hemolymph lipid concentration. Perfusate from CC incubated in proctolin contained material with similar biological activity to AKH. Proctolin was also found to significantly increase the synthesis and release of JH from locust CA, with the increase being greatest from CAs that had a relatively low basal rate of JH biosynthesis (<35 pmol h(-1) per CA). In contrast, proctolin did not alter the synthesis and release of JH from the cockroach CA. These results suggest that proctolin may act as a releasing factor for AKHs and JH in the locust but does not act as a releasing factor for JH in the cockroach.     

Kalirin/Trio Rho guanine nucleotide exchange factors regulate a novel step in secretory granule maturation

The molecular mechanisms involved in the maturation of secretory granules, organelles that store hormones and neuropeptides, are poorly understood. As granule content proteins are processed, the composition of granule membranes changes, yielding constitutive-like secretion of immature content proteins and producing secretagogue-responsive mature granules. Constitutive-like secretion was not previously recognized as a process subject to regulation. We show that Kalirin and Trio, homologous Rho guanine nucleotide exchange factors (GEFs), which interact with a secretory granule resident protein, modulate cargo secretion from immature granules. Some of the Kalirin and Trio isoforms expressed in neuroendocrine cells colocalize with immature granules. Overexpression of their N-terminal GEF domain (GEF1) enhances secretion from immature granules, depleting cells of secretory cargo in the absence of secretagogue. This response requires GEF1 activity and is mimicked by Kalirin/Trio substrates Rac1 and RhoG. Accordingly, selective pharmacological inhibition of endogenous GEF1 activity decreases secretagogue-independent release of hormone precursors, accumulating product peptide in mature secretory granules. Kalirin/Trio modulation of cargo secretion from immature granules provides secretory cells with an extra layer of control over the sets of peptides released. Control of this step enhances the range of physiological responses that can be elicited, whereas lack of control could have pathological consequences.     

Adipokinetic hormone functions that are not associated with insect flight

Abstract This review deals with some lesser known functions of adipokinetic hormones (AKHs), specifically those that are not associated directly with flight activity. The data summarized and discussed relate to AKHs in insects that have lost the ability to fly and use exclusively and/or mostly walking for their locomotion; and to activation of pathways that do not lead directly to production and subsequent rapid consumption of energy, but help the insect to combat stress situations. Emphasis is placed on AKH‐stimulated walking activities in Pyrrhocoris apterus, Gryllus bimaculatus, Periplaneta americana and Drosophila mellanogaster; diel fluctuations in AKH activities; the actions of AKH in alternative stress situations in which infection, toxins and other kinds of stressors interact; and the role of AKHs in anabolic processes and egg production. Possible mechanisms of action are proposed when justified by available knowledge.     

Structure and function of adipokinetic hormones of the large white butterfly Pieris brassicae

The large white butterfly Pieris brassicae L. (also called cabbage white) is very common in Europe, Asia and the northern region of Africa, and has also been found in South Africa during approximately the last 20 years. The species is considered a pest insect, with larvae attacking brassicaceous crops. The adult is a strong migratory flyer and new territory can be infested this way. As a first step to investigate methods for combating this pest species, the present study aims to determine the complement of adipokinetic peptides, here generically referred to as adipokinetic hormones (AKHs), which are required to regulate the mobilization of fuels for insect flight. Biological assays, as well as mass spectrometry, reveal information about the presence, structure and function of AKHs in P. brassicae: a methanolic extract of the corpora cardiaca has hypertrehalosaemic activity in cockroaches, does not cause hyperlipaemia in locusts, and has adipokinetic activity in P. brassicae itself. Liquid‐chromatography electrospray ion trap mass spectrometry reveals three peptides that can be associated with the AKH family: the non‐amidated undecapeptide Vanca‐AKH (pELTFTSSWGGK‐OH), the nonapeptide Manse‐AKH (pELTFTSSWG amide) and the novel octapeptide Piebr‐AKH (pELTFSSGW amide). Sequence confirmation of all three assigned structures is obtained from matching mass spectrometry spectra from synthetic and native peptides. Moreover, the synthetic peptides Manse‐AKH and Piebr‐AKH have significant hyperlipaemic (=adipokinetic) activity when injected into newly‐emerged adult cabbage white butterflies. The non‐amidated Vanca‐AKH is, apparently, incompletely processed Manse‐AKH without hormonal activity. Simulated dispersal flight is able to release AKHs, as indicated by the higher concentration of lipids in the haemolymph of adult P. brassicae after activity and rest periods.     

Processing of pro-islet amyloid polypeptide in the constitutive and regulated secretory pathways of beta cells

Islet amyloid is a pathologic characteristic of the pancreas in type 2 diabetes comprised mainly of the beta-cell peptide islet amyloid polypeptide (IAPP; amylin). We used a pulse-chase approach to investigate the kinetics of processing and secretion of the IAPP precursor, proIAPP, in beta cells. By only 20 min after synthesis, a COOH-terminally processed proIAPP intermediate (approximately 6 kDa) was already present in beta cells. Formation of this NH2-terminally extended intermediate was not prevented by arresting secretory pathway transport at the trans-Golgi network (TGN) by either brefeldin A or temperature blockade, suggesting that this initial cleavage step occurs in the TGN before entry of (pro)IAPP into granules. Mature IAPP (approximately 4 kDa) was not detected until 60 min of chase, suggesting that NH2-terminal cleavage occurs in granules. Cells chased in low glucose without Ca2+ or with diazoxide, to block regulated release, secreted both proIAPP (approximately 8 kDa) and a partially processed form (approximately 6 kDa) via the constitutive secretory pathway. Stimulation of regulated secretion resulted in secretion primarily of mature IAPP as well as low levels of both unprocessed (approximately 8 kDa) and partially processed (approximately 6 kDa) proIAPP. We conclude that normal processing of proIAPP is a two-step process initiated by cleavage at its COOH terminus (likely by prohormone convertase 1/3 in the TGN) followed by cleavage at its NH2 terminus (by prohormone convertase 2 in granules) to form IAPP. Both proIAPP and its NH2-terminally extended intermediate appear to be normal secretory products of the beta cell that can be released via either the regulated or constitutive secretory pathways.     

The adipokinetic hormone of Mantodea in comparison to other Dictyoptera

Six species of the order Mantodea (praying mantises) are investigated for the presence and sequence of putative adipokinetic hormones (AKHs). The selected species span a wide evolutionary range of various families and subfamilies of the clade Mantodea. The corpora cardiaca of the different species are dissected, methanolic extracts prepared, peptides separated by liquid chromatography, and AKHs detected and sequenced by ion trap mass spectrometry. All six species investigated contain an octapeptide with the primary structure pGlu‐Val‐Asn‐Phe‐Thr‐Pro‐Asn‐Trp amide, which is code‐named Emppe‐AKH and had been found earlier in three other species of Mantodea. Conspecific bioassays with the species Creoboter sp. (family Hymenopodidae) reveal an adipokinetic but not a hypertrehalosemic function of Emppe‐AKH. Comparison with other members of the Dictyoptera (cockroaches, termites) show that Emppe‐AKH is only found in certain termites, which have been recently placed into the Blattaria (cockroaches) as sister group to the family Cryptocercidae. Termites and cockroaches both show biodiversity in the sequence of AKHs, and some cockroach species even contain two AKHs. In contrast, all praying mantises—irrespective of their phylogenetic position—synthesize uniformly only one and the same octapeptide Emppe‐AKH.